McQuay RCS015 Installation Manual

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Installation and Maintenance Manual IM 738-2

RoofPak™ Singlezone Roof Mounted Heating and Cooling Units

RPS/RDT/RFS/RCS 015-135C

Group: Applied Systems

Part Number: IM 738

Date: June 2006

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Unit Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Compressor Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Gas Burner Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Hazard Identification Information . . . . . . . . . . . . . . . . . . . . . . . 3

Unit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Typical Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . 6

Condenser Fan Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . 8

Refrigeration Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Control Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Controls, Settings, and Functions . . . . . . . . . . . . . . . . . . . . . 22

Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Unit Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Ventilation Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Overhead Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

IBC Seismic Compliant Units . . . . . . . . . . . . . . . . . . . . . . . . 30

Roof Curb Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Post and Rail Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Post and Rail Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Rigging and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Reassembly of Split Units . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

RPS/RDT Factory Split at Condensing Unit . . . . . . . . . . . . . 42

RFS/RCS Permanent Split Systems . . . . . . . . . . . . . . . . . . . 47

Unit Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Steam Coil Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Steam Piping Recommendations . . . . . . . . . . . . . . . . . . . . . 54

Steam Trap Recommendations . . . . . . . . . . . . . . . . . . . . . . . 55

Damper Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Cabinet Weather Protection . . . . . . . . . . . . . . . . . . . . . . . . . 58

Installing Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Installing Duct Static Pressure Sensor Taps . . . . . . . . . . . . . 59

Installing Building Static Pressure Sensor Taps . . . . . . . . . . 60

Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Field Power Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Field Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Preparing Unit for Operation . . . . . . . . . . . . . . . . . . . . . 65

Spring Isolated Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Relief Damper Tie-Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Adjusting Scroll Dampers . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Adjusting Supply Fan Thrust Restraints . . . . . . . . . . . . . . . . 66

Sequences of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Power-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Economizer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Mechanical Cooling Operation . . . . . . . . . . . . . . . . . . . . . . . 68

Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Unit Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Enthalpy Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Hot Gas Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

SpeedTrol™ (N/A Unit Sizes 015C to 030C) . . . . . . . . . . . . 99

External Time Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Smoke and Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . 100

Smoke Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Entering Fan Temperature Sensor . . . . . . . . . . . . . . . . . . . 102

Duct High Pressure Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

MicroTech II™ Remote User Interface (UI) . . . . . . . . . . . . . 102

Variable Frequency Drive Operation . . . . . . . . . . . . . . . . . . 104

Convenience Receptacle/Section Lights . . . . . . . . . . . . . . . 104

DesignFlow™ Outdoor Air Damper Option . . . . . . . . . . . . . 104

Propeller Exhaust Fan Option . . . . . . . . . . . . . . . . . . . . . . . 107

Exhaust Fan On/Off Control . . . . . . . . . . . . . . . . . . . . . . . . . 109

Ultraviolet Lights Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Ultraviolet Light Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Check, Test, and Start Procedures . . . . . . . . . . . . . . 112

Servicing Control Panel Components . . . . . . . . . . . . . . . . . 112

Before Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Power Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Fan Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Economizer Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Compressor Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Scroll Compressor Rotational Direction (sizes 15 to 105) . . 114

Oil Pressure (sizes 115 to 135C only) . . . . . . . . . . . . . . . . . 115

Heating System Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Air Balancing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Sheave Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Drive Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Mounting and Adjusting Motor Sheaves . . . . . . . . . . . . . . . 119

Final Control Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Servicing Control Panel Components . . . . . . . . . . . . . . . . . 126

Planned Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Unit Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Bearing Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Setscrews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Supply Fan Wheel-to-Funnel Alignment . . . . . . . . . . . . . . . 130

Refrigerant Leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Refrigerant Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Servicing Refrigerant Sensors or Switches . . . . . . . . . . . . . 131

Winterizing Water Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Control Panel Components . . . . . . . . . . . . . . . . . . . . . . . . . 132

Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Service and Warranty Procedure . . . . . . . . . . . . . . . . 137

Scroll Compressor (sizes 15 to 105C) . . . . . . . . . . . . . . . . . 137

Reciprocating Compressors (sizes 115 to 135C) . . . . . . . . 137

All Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Limited Product Warranty (North America) . . . . . . 139

Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Sole Remedy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Rooftop Equipment Warranty Regist. Form . . . . . 140

Introduction

This manual provides general information about the “C” vintage McQuay RoofPak applied rooftop unit, models RPS, RDT, RFS, and RCS. In addition to an overall description of the unit, it includes mechanical and electrical installation procedures, commissioning procedures, sequence of operation information, and maintenance instructions. For further information on the optional forced draft gas-fired furnace, refer to Bulletin No. IM 684 or IM 685.

The MicroTech II applied rooftop unit controller is available on “C” vintage applied rooftop units. For a detailed description of the MicroTech II components, input/output configurations, field wiring options, requirements, and service procedures, see IM 696-3. For operation and information on using and programming the MicroTech II unit controller, refer to the appropriate operation manual (see Table 1).

For a description of operation and information on using the keypad to view data and set parameters, refer to the appropriate program-specific operation manual (see Table 1).

Table 1: Program specific rooftop unit operation literature

Rooftop unit control configuration

VFDs Vendor IM manuals

Discharge Air Control (VAV or CAV) OM 137-2

Space Comfort Control

(CAV-Zone temperature control)

Operation manual bulletin

number

OM 138-2

Unit Nameplate

The unit nameplate is located on the outside lower right corner of the main control box door. It includes the unit model number, serial number, unit part number, electrical characteristics, and refrigerant charge.

On units that utilize the tandem compressor design, each compressor includes an individual nameplate along with a nameplate identifying the tandem compressors.

Gas Burner Nameplate

On units that include gas heat, the nameplate is located on the lower right corner of the main control box door. It includes the burner model number, minimum/maximum input, maximum temperature rise, and minimum cfm.

On units that utilize the tandem scroll compressor design, each compressor includes an individual nameplate along with a nameplate identifying the tandem compressors.

On units that utilize the tandem reciprocating design, each compressor includes an individual nameplate.

Hazard Identification Information

WARNING

Warnings indicate potentially hazardous situations, which can result in property damage, severe personal injury, or death if not avoided.

CAUTION

Cautions indicate potentially hazardous situations, which can result in personal injury or equipment damage if not avoided.

Compressor Nameplate

On units with a single compressor on each circuit, the compressor includes one compressor nameplate.

McQuay IM 738-2 3

Introduction

Figure 1: Nomenclature

R P S – 030 C S E

RoofPak

Unit configuration P = Heating, mechanical cooling F = Heating, future mechanical cooling C = Condensing section only D = Draw through cooling

Blow through cooling = S Draw through cooling = T

Nominal capacity (tons) RPS, RFS, RCS, RDT: 015, 018, 020, 025, 030, 036, 040, 045, 050, 060, 070, 075, 080, 090, 105, 115, 125, 135

Heat medium A = Natural gas E = Electric S = Steam W = Hot water Y = None (cooling only)

Cooling coil size S=Standard (low airflow) L =Large (high airflow)

Design vintage

4 McQuay IM 738-2

Unit Description

Figure 2: RPS/RDT/RFS/RCS unit

Introduction

R P S / R D T

R F S

R C S

McQuay IM 738-2 5

Introduction

Typical Component Locations

Figure 2 shows an RPS/RDT/RFS/RCS unit. Figure 3 shows a typical RPS unit with the locations of the major components.

Figure 3: Typical component locations—RPS units

Top View

Outside and return air dampersa

Side View

Exhaust hood

Bottom return air opening

Filter section

Supply air fan

Figure 4 on page 7 shows a typical RDT unit with the locations of the major components.

These figures are for general information only. See the project’s certified submittals for actual specific dimensions and locations.

Bottom discharge air opening

Power and control entrances

Evaporator coil

Discharge plenum (main control panel)

Optional back return opening

Return air

Return airReturn air fan

Outside air louvers

Heat section (natural gas, oil, steam, hot water, electric

Air cooled condenser

6 McQuay IM 738-2

Figure 4: Component locations—RDT units

Top View

Introduction

Bottom supply air opening

1.50 MPT drain

Bottom return opening

Side View

Return air plenum

Exhaust dampers

Optional back return air opening

Return air fan

Optional outside & return air dampers

Filter section

Outside air louvers (both sides)

Control entrances 7/8" dia K.O.

DX coil section

Evaporator coils

Power entrances 3" dia K.O.

Supply fan section

McQuay IM 738-2 7

Introduction

Condenser Fan Arrangement

Table 2 shows the condenser fan numbering conventions and locations for each unit size.

Table 2: Condenser fan arrangement

Unit size Refrigerant circuit Arrangement Unit size Refrigerant circuit Arrangement

COND

015C 018C 020C

1 or 2

AHU

075C 080C 090C

025C 030C 1 or 2

036C 040C

045C 050C

060C 070C

105C

115 C

1 125C 135C

8 McQuay IM 738-2

Introduction

Refrigeration Piping

This section presents the unit refrigeration piping diagrams for the various available configurations.

Figure 5: Circuit schematic

A - Compressor (1, 2, or 3 per circuit)† B - Discharge line †

Figure 6: Condenser piping, scroll compressors, one to three compressors per circuit are provided (015 to 105C)

Legend

1 - Discharge shut-off valve—Circuit #1 2 - Liquid shut-off valve—Circuit #1 3 - Liquid shut-off valve—Circuit #2 4 - Discharge shut-off valve—Circuit #2

C - Condenser coil † D - Evaporator coil* E - Manual shutoff valve† F - Filter-drier* G - Liquid line solenoid valve* H - Sightglass* I - Liquid line*† J - Suction line K - Thermal expansion valve* L - Distributor* M - Hot gas bypass and solenoid valve (optional)*† N - Hot gas bypass lines (optional)* †

*Supplied on RFS units †Supplied on RCS units

Compressor #1

Discharge lines Circuit #1 Circuit #2

Compressor #3

Liquid lines Circuit #1 Circuit #2

Compressor #4

Compressor #2

Optional hot gas bypass lines Circuit #1 Circuit #2

Suction lines Circuit #1 Circuit #2

McQuay IM 738-2 9

Introduction

Figure 7: Condenser piping, four reciprocating compressors (115 to 135C)

Legend

1 - Discharge Line Service Valve 2 - Discharge Muffler 3 - High Pressure Relief Valve 4 - Liquid Line Manual Shut-off Valve 5 - Suction Line Service Valve

10 McQuay IM 738-2

Figure 8: Air handler piping (flat DX)

circu

Legend

1 - Filter-drier 2 - Liquid line solenoid valve 3 - Sightglass 4 - Hot gas bypass and solenoid valve (optional) 5 - Thermostatic expansion valve 6 - Distributor

Introduction

Figure 9: Air handler piping (staggered DX)

Legend

1 - Filter-drier 2 - Liquid line solenoid valve 3 - Sightglass 4 - Hot gas bypass and solenoid valve (optional) 5 - Thermostatic expansion valve 6 - Distributor

Liquid line circuit #1

Optional hot gas bypass line circuit #1 circuit #2

Air handler section

Condenser section

Circuit #1

Circuit #2

Liquid line circuit #2

Suction line circuit #1

it #2

McQuay IM 738-2 11

Introduction

Control Locations

Figure 10 (RPS Units) and Figure 11 on page 13 (RDT Units) show the locations of the various control components mounted throughout the units. See “Control Panel” on page 14 for the locations of control components mounted in control panels.

Figure 10: Control locations—RPS units

FS1

SD2

(optional)

Return air

economizer

C19

RAT

Filter

section

Supply

fan

section

LT11

(opt io nal )

OAT

S11, REC11

(optional)

Heat

section

OAE

ACT3

ACT6 (optional)

RAE (optional)

section

LT10

S10, REC10

PC5

Additional information is included in Table 3 on page 22 and the wiring diagram legend, which is included in “Wiring Diagrams” on page 71.Components mounted in the blowthrough section are located in the same position within the draw-through section.

SC11, 12 (optional)

C11, 12 (optional)

SV1

SV5 (optional)

SV6 (optional)

ACT5 (optional)

HP1-2, HP3-4 (optional)

LP1-2

HTR1-2, HTR3-4 (optional)

SV2

Disc harge

HL22

plenum section

EFT

(optional)

Condensor

section

SD1

PC7

DAT (optional)

VM1

(optional)

12 McQuay IM 738-2

Figure 11: Control locations—RDT units

section

Filter

section

Economizer

return air

Heat

section

Supply fan

discharge

plenum

section

Condenser

section

SC11, 21 (optional)

SV1, 2

Introduction

C11, 21 (optional)

HP1-2, LP1-2 HTR1-2, U1/U2 HP3-4 (optional) HTR3-4 (optional)

C19, 20

(optional)

RAT

LT11 (optional)

S11, REC11

SD2

(optional)

RAE

(optional)

ACT3

ACT6

PC5

OAE

OAT

VM1

(optional)

FS1

(optional)

DAT

LT10 (optional)

S10, REC10 (optional)

SD1 (optional)

SV5, 6 (optional)

McQuay IM 738-2 13

Introduction

Control Panel

The unit control panels and their locations are shown in the following figures. These figures show a typical unit

Figure 12: Control panel locations

Prop exhaust (optional)

not shown)

(

VFDs, line reactors, and

manual bypass (optional)

Electric heat control panel (optional)

configuration. Specific unit configurations may differ slightly from these figures depending on the particular unit options.

Supply fan section

Condenser section

Main control panel

14 McQuay IM 738-2

Figure 13: Typical main control panel, 015 to 040, 460 volt

Introduction

See separate

detail, page 17.

McQuay IM 738-2 15

Introduction

Figure 14: Typical main control panel, 045 to 075, 460 volt

See separate

detail, page 17.

16 McQuay IM 738-2

Figure 15: Typical main control panel, 080 to 135, 460 volt

Introduction

Figure 16:

McQuay IM 738-2 17

Introduction

Figure 17: Typical gas heat panel, 1000 MBH Figure 18: Typical propeller exhaust panel, 3 fans, 460 volt

R22

TD10

R20

R23 R21

LS2

LS1

Figure 19: VFD bypass panel, 40 HP, 460 volt)

FSG

FSG Tim

18 McQuay IM 738-2

Figure 20: RCS control panel with MicroTech II, 015 to 040C

Figure 21: RCS control panel with MicroTech II, RPS 045 to 075C

Introduction

Figure 22: RCS control panel with MicroTech II, RPS 080 to 135C

McQuay IM 738-2 19

Introduction

Figure 23: Electric heat panel, sizes 15 to 40C

FB33 FB32 FB31

M33 M32 M31

FB43 FB42 FB41

M41 M42 M41

SR2

SR3

SR1

TB11

Figure 25: Electric heat panel, sizes 80 to 135

FB31FB32FB33

M31M32M33

FB34FB44

M34M44

FB41FB42FB43

M41M42M43

H53

TB11

PB3

Figure 24: Electric heat panel, sizes 45 to 75C

FB31FB32FB33 M31M32M33

FB41FB42FB43

M42

M41M43

GLG3

DS3

H53

TB11

GLG3

DS3

20 McQuay IM 738-2

Figure 26: Harness plug connector detail

RATS OATSDATS

FP1 OPEN1EPTS

AFD10 AFD20

SV12 SV56

ACT3 OPEN2

OAE PC7PC5

Introduction

HL22 OPEN3

GSHT1 GSHT2

SD1 SD2

DFRH DFLH OPEN4

COMP1 COMP2

COMP3 COMP4

COMP6COMP5

LT11LT1 0

LT OP1 LT OP2

McQuay IM 738-2 21

Introduction

Controls, Settings, and Functions

Table 3 below lists all of the unit control devices and associated information.

Table 3: Controls, settings, and functions

Symb

CS1 &

DAT

DHL

EFT

FP1, 2

FS1

HP1,

3 & 4

LP1, 2

MCB

MP1–

OAE

OAT

PC5

Description Function

Switch (toggle), refrigerant circuit

Discharge air temperature sensor

Duct high limit switch

Entering fan air temperature sensor

Evaporator frost protection

Freezestat

High pressure control

Low pressure control

Main control board Processes input information

Compressor motor protector

Enthalpy control (electromechanical)

Enthalpy control (electronic)

Outside air temperature sensor

Dirty filter switch Senses filter pressure drop

Shuts off compressor control circuits manually

Senses discharge air temperature

Prevents excessive VAV duct pressures; shuts off fan

Senses entering fan air temperature

Senses low refrigerant temperature

Shuts off fans, opens heating valve, and closes outdoor damper if low air temperature at coil is detected Stops compressor when refrigerant discharge pressure is too high

Stops compressor when suction pressure is too low (used for pumpdown)

Senses motor winding temperature, shuts off compressor on high temperature. Notes:

1.Unit size 018C compressors include internal motor protector.

2.Unit sizes 020C–036C, circuit #1 compressors include internal motor protector (refer to unit wiring diagram).

Returns outside air dampers to minimum position when enthalpy is too high

Returns outside air dampers to minimum position when outside air enthalpy is higher than return air empalthy (use RAE)

Senses outside air temperature

Rese

N/A

Auto

N/A

Auto

Manu

al (relay latche

Auto Compressor

N/A

Auto

3400

ohms

Auto

N/A N/A N/A

Auto

Location Setting Range Differential Part no.

Main control

panel

Discharge air

section

Main control

panel

Inlet of supply

fan

Return bends

of evaporative

coil

Heating

section

Compressor

Main control

box

Compressor

junction box

Economizer

section

Economizer

section

First filter

section

N/A N/A N/A 01355000

N/A N/A

3.5" w.c

(871.8 Pa)

N/A N/A

Opens at

30°F

Closes at

45°F

38°F (3°C)

or as

required

See page

131.

See page

131.

N/A N/A N/A

9 K–18 K

ohms

“B” or as required

Fully CW

past “D”

(when used

with RAE)

As required

0.05–5.0" wc (12.5–1245.4

Pa)

N/A N/A

35°F–45°F (2°C–7°C)

N/A

700 ohms cold N/A

A–D

A–D N/A

.05-5" wc

(12.5–1245.4

Pa)

.05" wc

(12.5 Pa),

fixed

12°F (7°C),

fixed

100 psi

(689 kPa)

25 psi

(172 kPa)

Temperature:

3.5°F (2°C) Humidity:

5% fixed

.05" wc

(12.5 Pa)

06000470

06549380

06000470

07250190

06583000

04735612

047356111

06000610

04469150

03070670

04926220

06000470

06549380

22 McQuay IM 738-2

Table 3: Controls, settings, and functions (continued)

Symb

PC6

PC7

PS1,

RAE

RAT

SD1

SD2

SPS1

SPS2

SV1,

SV5,

Description Function

Dirty filter switch Senses filter pressure drop

Airflow proving switch

Pumpdown switch Used to manually pump down

Return air enthalpy sensor

Return air temperature sensor

Smoke detector, supply air

Smoke detector, return air

Static pressure sensor duct #1

Static pressure sensor duct #2

Static pressure sensor: building (space) pressure

Solenoid valve (liquid line)

Solenoid valve (hot gas bypass)

System switch

ON-OFF-AUTO switch

Senses supply fan pressure to prove airflow

compressor

Used to compare return air enthalpy to outside air enthalpy (used with OAE)

Senses return air temperature

Initiates unit shutdown if smoke is detected

Converts static pressure signals to voltage signals

Converts static pressure signals to voltage signals and sends them to MicroTech II controller

Converts static pressure signals to voltage signals.

Closes liquid line for pumpdown

Closes hot gas bypass line for pump-down

Shuts off entire control circuit (except crankcase heaters)

Used to manually switch unit

Rese

Auto

N/A

ManualDischarge air

ManualReturn air

N/A

Location Setting Range Differential Part no.

Final filter

section

Supply fan

section

Condenser control box

Economizer

section

Return air

section

Main control

box

Main control

box

Main control

box

Condenser

section

Condenser

section

Main control

box

Main control

box

Introduction

As required

.10" wc (25

Pa)

N/A N/A N/A 01355000

N/A N/A N/A

N/A N/A

N/A N/A N/A 04925001

N/A

N/A N/A N/A

N/A N/A N/A 111011001

N/A N/A N/A

.05-5" wc

(12.5–1245.4

Pa)

.03-1.40" wc

(7.5–348 Pa)

0–5" wc (0–1245.4 Pa) 1–6 V (dc) out

-025–0.25" wc

(-62.3–62.3 Pa)

1–5 V (dc) out

.05" wc

(12.5 Pa)

.03" wc

(7.5 Pa),

fixed

N/A

06549380

06001580

04926220

06000470

04954500

00135500

See parts

catalog

FanTrol

The FanTrol, provided on all units, is a method of head pressure control that automatically cycles the condenser fans in response to ambient air temperature. This feature maintains

head pressure and allows the unit to run at low ambient air temperatures.

RPS/RDT and RCS units have two independent refrigerant circuits with one to four condenser fans being controlled independently by the ambient air temperature of each circuit.

Table 4: R-22 FanTrol setpoints in °F with MicroTech II controls

RPS RCS RDT RPR

015 to 020C0 5 60 5 ———— 025 to 030C0 5 65 5 ————

0360 5 70 5 ————

045 to 045C0 5 65 5 ————

0500 5 60 5 ———— 0600 5255705—— 0700 5405705——

075 to 090C 0 5 65 5 75 5 0 5

1050505585705 1150505555755 1250 5655355805 1350 5555255655

Setpoint Differential Setpoint Differential Setpoint Differential Setpoint Differential

B05 B06 B07 B08

McQuay IM 738-2 23

Degrees Farenheit

Introduction

Table 5: R-407C FanTrol setpoints in °F with MicroTech II controls

RPS, RCS, RDT

Setpoint Differential Setpoint Differential Setpoint Differential Setpoint Differential

015 0 5 60 5 018 to 020C0505———— 025 to 036C0 5 65 5 ————

040 0 5 60 6

0450 5 55 5 ————

050 0 5 50 5 — —

0600 5155705——

0700 5305705——

0750 5655755 0 5 080 to 090C 0 5 65 5 75 5 0 5

1050505525705

1150505455755

1250 5555305805

1350 5455205655

B05 B06 B07 B08

Degrees Farenheit

24 McQuay IM 738-2

Mechanical Installation

Note – The installation of this equipment shall be in accordance

with the regulations of authorities having jurisdiction and all applicable codes. It is the responsibility of the installer to determine and follow the applicable codes. Low head pressure may lead to poor, erratic refrigerant feed control at the thermostatic expansion valve. The units have automatic control of the condenser fans which should provide adequate head pressure control down to 50°F (10°C) provided the unit is not exposed to windy conditions. The system designer is responsible for assuring the condensing section is not exposed to excessive wind or air recirculation.

CAUTION

Sharp edges on sheet metal and fasteners can cause personal injury. This equipment must be installed, operated, and serviced only by an experienced installation company and fully trained personnel.

Receiving Inspection

When the equipment is received, all items should be carefully checked against the bill of lading to be sure all crates and

Figure 27: Service clearances

72"

(1829 mm)

cartons have been received. If the unit has become dirty during shipment (winter road chemicals are of particular concern), clean it when received.

All units should be inspected carefully for damage when received. Report all shipping damage to the carrier and file a claim. In most cases, equipment ships F.O.B. factory and claims for freight damage should be filed by the consignee.

Before unloading the unit, check the unit nameplate to make sure the voltage complies with the power supply available.

Unit Clearances

Service Clearance

Allow an approximate service clearance as indicated in Figure 27. Also, McQuay recommends providing a roof walkway to the rooftop unit as well as along two sides of the unit that provide access to most controls and serviceable components.

60"

(1524 mm)

Roof walkway

To roof access

location

60"

(1524 mm)

96"

(2438 mm)

Varies with unit arrangement

Refer to certified drawing & note.

Ventilation Clearance

Below are minimum ventilation clearance recommendations. The system designer must consider each application and provide adequate ventilation. If this is not done, the unit will not perform properly.

Unit(s) surrounded by a screen or a fence:

60"

(1524 mm)

Legend:

A = Return air section B = Filter section C = Cooling section D = Cooling/supply fan section E = Heat section F = Discharge plenum section

The bottom of the screen or fence should be at least 1 ft. (305 mm) above the roof surface.

2 The distance between the unit and a screen or fence should

be as described in Figure 27.

3 The distance between any two units within a screen or

fence should be at least 120" (3048 mm).

McQuay IM 738-2 25

Mechanical Installation

Unit(s) surrounded by solid walls:

1 If there are walls on one or two adjacent sides of the unit,

the walls may be any height. If there are walls on more than two adjacent sides of the unit, the walls should not be higher than the unit.

2 The distance between the unit and the wall should be at

least 96" (2438 mm) on all sides of the unit.

3 The distance between any two units within the walls should

be at least 120" (3048 mm).

Do not locate outside air intakes near exhaust vents or other sources of contaminated air.

If the unit is installed where windy conditions are common, install wind screens around the unit, maintaining the clearances specified (see Figure 28). This is particularly important to prevent blowing snow from entering the outside air intake and to maintain adequate head pressure control when

Figure 28: Overhead clearance

Overhead canopy

mechanical cooling is required at low outdoor air temperatures.

Overhead Clearance

1 Unit(s) surrounded by screens or solid walls must have no

overhead obstructions over any part of the unit.

2 The area above the condenser must be installed

unobstructed to allow vertical air discharge.

3 The following restrictions must be observed for overhead

obstructions above the air handler section (see Figure 28):

a There must be no overhead obstructions above the

furnace flue, or within 9" (229 mm) of the flue box.

b Overhead obstructions must be no less than 96"

(2438 mm) above the top of the unit.

c There must be no overhead obstructions in the areas

above the outside air and exhaust dampers that are farther than 24" (610 mm) from the side of the unit.

24" (610 mm) maximum

96" (2438 mm)

minimum,

top of unit to

permanent

overhead

obstruction

9" (229 mm) minimum to flue box, typical all sides

Flue box

24" (610 mm) maximum

26 McQuay IM 738-2

Mechanical Installation

Roof Curb Assembly and Installation

Locate the roof curb and unit on a portion of the roof that can support the weight of the unit. The unit must be supported to prevent bending or twisting of the machine.

If building construction allows sound and vibration into the occupied space, locate the unit over a non-critical area. It is

the responsibility of the system designer to make adequate provisions for noise and vibration in the occupied space.

WARNING

Mold can cause personal injury. Some materials such as gypsum wall board can promote mold growth when damp. Such materials must be protected from moisture that can enter units during maintenance or normal operation.

Install the curb and unit level to allow the condensate drain to flow properly and allow service access doors to open and close without binding.

Figure 29: RCS roof curb assembly

6 "

" Z Z "

6 "

1 . U n i t B a s e

2 . G a l v a n i z e d C u r b 3 . G a l v a n i z e d C u i r b C o v e r 4 . 2 x 4 N a i l e r S t r i p 5 . R i g i d I n s u l a t i o

6 "

6 . C a n t S t r i p ( n o t f u r n i s h e d ) 7 . F l a s h i n g ( n o t f u r n i s h e d ) 8 . C u r b G a s k e t i n g 9 . I n s u G a l v a n i z e d C u r b ( n o t f u r n i s h e d ) 1 0 . R o o f i n g M a t e r i a l ( n o t f u r n i s h e d )

n ( n o t f u r n i s h e d )

l a t i o n b e t w e e n

Integral supply and return air duct flanges are provided with the RPS/RFS roof curb, allowing connection of duct work to the curb before the unit is set. The gasketed top surface of the duct flanges seals against the unit when it is set on the curb. These flanges must not support the total weight of the duct work. See “Installing Ductwork” on page 58for details on duct connections. It is critical that the condensate drain side of the unit be no higher than the opposite side.

Assembly of a typical RPS/RDT roof curb is shown in Figure 30 on page 28. Parts A through K are common to all units having bottom return openings. Depending on the unit length, Parts L and M may be included with the roof curb kit to create the correct overall curb length.

Figure 29 shows the assembly of the RCS roof curb.

RCS unit size

015C–030C 31.0 787

6 "

D e t a i l C

1 0

036C & 040C 94.0 2057

045C–060C 62.0 1575 070C–105C 100.0 2540 115C–135C 120.0 3048

in. mm

“ZZ”

RCS Assembly instructions

1 Set curbing parts “A” (Figure 29) in place making sure that

the orientation complies with the assembly instructions. Check alignment of all mating bolt holes.

2 Bolt curbing parts together using fasteners provided.

3 Curb must be level from side to side and over its length.

4 Weld curbing in place. Caulk all seams watertight and

insulate between channels.

5 Flash curbing into roof as shown in Detail C.

RPS/RDT Assembly instructions

1 Set curbing parts A through K per dimensions shown over

roof opening or on a level surface (see Figure 30 on page 28). Note location of return and supply air openings.

2 If applicable, set other curbing parts (D, L, M, etc.) in place

making sure that the orientation complies with the assembly instructions (see Detail A). Check alignment of

3 Bolt curbing parts together using fasteners provided.

Tighten all bolts finger tight.

4 Square entire curbing assembly and securely tighten all

bolts.

5 Position curb assembly over roof openings. Curb must be

level from side to side and over its length. Check that top surface of the curb is flat with no bowing or sagging.

6 Weld curbing in place. Caulk all seams watertight. Remove

backing from 0.25" (6 mm) thick × 1.50" (38 mm) wide gasketing and apply to surfaces shown by cross-hatching.

7 Flash curbing into roof as shown in Detail B.

8 Parts E and F are not required on units with no return shaft

within the curb perimeter.

9 Parts G and H are not required on units with no supply shaft

within the curb perimeter.

10 Be sure that electrical connections are coordinated (see

Figure 36).

all mating bolt holes.

McQuay IM 738-2 27

Mechanical Installation

Figure 30: RPS/RFS roof curb assembly

28 McQuay IM 738-2

Mechanical Installation

Table 6: Roof curb assembly dimensions

Unit size Fan

None 24.0 610 82.0 2083 6.8 173 1.5 38 015C–030C 45.9 1165 20.0 508

015–040C

045C–075C All units 38.0 965 87.0 2210 8.8 222 3.5 89 105C—135C 113 2870 46.0 1168

80C–135C All units 62.0 1575 87.0 2210 8.8 222 3.5 89

Note: These dimensions do not apply to units with energy recovery wheels.

(2) 15” FC 24.0 610 82.0 2083 6.8 173 1.5 38

30" AF 30.0 762 76.0 1930 6.8 173 4.5 114 045C–075C 77.0 1956 28.0 712 40" AF 36.0 914 78.0 1981 14.8 376 3.5 89 80C–90C 113 2870 38.0 965

“X” “Y” “XX” “YY”

in mm in mm in mm in mm in mm in mm

Unit size

036C and

040C

“Z” “W”

94.0 2388 20.0 508

McQuay IM 738-2 29

Mechanical Installation

IBC Seismic Compliant Units

It is important to follow these installation instructions for all IBC Seismic compliant McQuay Rooftop units.

IBC Seismic compliant McQuay Rooftop units can be mounted to either a roof curb or a post and rail setup. If using a roof curb, it must be specifically designed for seismic restraint and be IBC seismic compliant (spring isolated or non-isolated type seismic roof curbs are available). Typical construction of a seismic rated roof curb is from structural steel framing and contains seismic hold down brackets for attachment of the rooftop unit (see Figure 31). Post and rail arrangements rated for seismic applications are also available (spring isolated or non-isolated).

IMPORTANT: An acceptable IBC seismic installation provides a direct positive attachment to both the building structure and the roof mounted equipment.

Refer to the roof curb manufacturer’s submittal drawings for actual roof curb assembly, attachment details and rigging instructions for both roof curb and post and rail arrangements.

Figure 31: Typical seismic roof curb (spring isolated)

Roof Curb Arrangement

1 Set the rooftop unit on the roof curb (McQuay Rooftop

units are designed to overhang from the roof curb).

2 Adjust the seismic hold down brackets so they come into

contact with the unit base per Figures 32 and 33 on page

31.

a The seismic hold down brackets should be adjustable

and accommodate the overhang of the rooftop unit.

b If the hold down bracket cannot reach the unit base, use

a shim spacer. See Figure 33 on page 31.

3 Weld each seismic hold down bracket (and shim spacer, if

required) to the unit base as shown in the acceptable weld zone detail in Figure 32 on page 31.

CAUTION

When welding unit to the curb, do not damage wiring (control panel side). Weld ONLY in the specified zone in the acceptable weld zone (see Figure 32 on page 31). Welding must comply with weld fillet size, etc. as indicated in Figure 32 on page 31.

Note – High temperature insulation is installed at the factory to

allow for field welding along the lower front edge region of the unit base.

Duct opening

Seismic hold down brackets

Structural steel frame

Seismic hold down brackets

Spring isolator

30 McQuay IM 738-2

Figure 32: Welding of hold down brackets—unit base, cross-sectional view

Unit power wiring (by factory)

Unit base

.25

Field attachment

Mechanical Installation

Unit control wiring (by factory)

weld

Weld zone

.50"

Acceptable weld zone

Figure 33: Shim spacers on hold down brackets

Shim

spacer

It may be necessary for the contractor to field fabricate spacers or new seismic hold-downs for rooftop units having larger overhang dimensions.

Unit power wiring

(by factory)

Unit base

High temp Insulation

Seismic hold down bracket

Unit control wiring (by factory)

Roof curb

Seismic hold

down bracket

Roof curb

McQuay IM 738-2 31

Mechanical Installation

Post and Rail Arrangement

1 Set the rooftop unit on the rails. The rails should run

lengthwise and support the entire unit base.

2 Weld both sides of the unit directly to each rail as shown in

Figures 34 and 35 on page 32. required is dependent on the length of the unit.

a Make the fillet welds 2 inches long, spaced 48 inches

apart on centers.

b Place the end welds 6 to 12 inches from the unit edge.

Figure 34: Welding of unit to rail—unit base, cross-sectional view

The total number of welds

Note – High temperature insulation is installed at the factory to

CAUTION

When welding unit to the curb, do not damage wiring (control panel side). Weld ONLY in the specified zone in the acceptable weld zone (see Figure 34 on page 32). Welding must comply with weld fillet size, etc. as indicated in Figure 34 on page 32.

allow for field welding along the lower front edge region of the unit base.

Unit base

.25

Weld zone

2–48

.50"

Acceptable weld zone

Figure 35: Weld locations for rail arrangement

6–12"

Unit power wiring

(by factory)

Unit base

Rail

Field attachment

weld

High temp insulation

Unit control wiring

(by factory)

Rail

Rooftop unit

.25

2–48

Weld every 48"

Rails

6–12"

32 McQuay IM 738-2

Figure 36: Typical power wire entrance, curb view (RPS/RFS 015C to 040C shown, refer to submittal)

Mechanical Installation

Detail A

20.0

OPNG

6.0

6.8

1.5

76.0

7.5

6.0

3.0 Dia. K.O.

RPS only

97.0

8.0

2Typ 4Typ

K.O.

OPNG

See Detail A

Unit length minus 6.4

12.1

5.1

3.4

0.9 Dia.

2.0

4.6

4.8

9.7

2.1

3.1

4.3

McQuay IM 738-2 33

Mechanical Installation

Post and Rail Mounting

When mounting by post and rail, run the structural support the full length of the unit. Locate the structural member at the base of the unit as shown in Figure 37, assuring the I-beam is well

supported by the structural member.

CAUTION

The unit must be level side to side and over the entire length. Equipment damage can result if the unit is not level.

If resilient material is placed between the unit and the rail, insert a heavy steel plate between the unit and the resilient material to distribute the load. Seal cabinet penetrations (electrical, piping, etc.) properly to protect against moisture and weather.

Figure 37: Post and rail mounting

hook should always be longer than the distance between the outer lifting points.

If the unit is stored at the construction site for an intermediate period, follow these additional precautions:

1 Support the unit well along the length of the base rail.

2 Level the unit (no twists or uneven ground surface).

3 Provide proper drainage around the unit to prevent flooding

of the equipment.

4 Provide adequate protection from vandalism, mechanical

contact, etc.

5 Securely close the doors.

6 If there are isolation dampers, make sure they are properly

installed and fully closed to prevent the entry of animals and debris through the supply and return air openings.

7 Cover the supply and return air openings on units without

isolation dampers.

Figure 38 shows an example of the rigging instruction label shipped with each unit.

WARNING

Use all lifting points. Improper lifting can cause severe personal injury and property damage.

Maximum recommended width for structural member is 5" (127 mm) to allow for adequate space for duct connections and electrical entry.

Table 7: “W” dimension (Figure 37)

Unit

015C-040C 94 2388 045C-135C 99 2538

Dimension “W”

inches mm

Rigging and Handling

Lifting brackets with 2" (51 mm) diameter holes are provided on the sides of the unit.

Use spreader bars, 96" to 100" (2438 to 2540 mm) wide, to prevent damage to the unit cabinet. Avoid twisting or uneven lifting of the unit. The cable length from the bracket to the

Figure 38: Rigging and handling instruction label

Unit has either four or six lifting points (four-point shown below).

Rigging cables must be at least as long as distance “A.”

Spreader bars required

Caution: Lifting points may not be symmetrical to center of

Lift only as indicated

gravity of unit. Balast or unequal cable lengths may be required.

CAUTION

Lifting points may not be symmetrical to the center of gravity of the unit. Ballast or unequal cable lengths may be required.

34 McQuay IM 738-2

Mechanical Installation

Lifting Points

To determine the required lifting cable lengths and whether four-point or six-point lifting is required, use Tables 10 and 11 and Figures 39 and 40.

Referring to Figure 39 and Figure 40, note that dimension A is the distance between the outer lifting points. The four outer rigging cables must be equal to or longer than dimension A. Dimension B shows the minimum distance between the outer and the inner lifting points for six-point lifting. Use this to roughly determine the required length of the middle cables for six-point lifting. Determine dimension A by subtracting dimensions X and Y from dimension Z (e.g., A = Z – X – Y).

• Where:

• Z = Total unit length in inches

(refer to certified drawings for this dimension).

• X = Outdoor/return air section length (refer to Table 10 for this dimension).

• Y = Refer to Table 11 for this dimension (see Figure 39 and Figure 40). If A ≤ 288" (7315 mm), 4-point lifting is sufficient.

• If A > 288" (7315 mm), 6-point lifting is required.

Table 8: Economizer section

Type of economizer

section

100% OA 0 0

Plenum 48” (1219 mm) 72” (1829 mm)

0–30% OA 48” (1219 mm) 72” (1829 mm)

0–100% economizer 72” (1829 mm) 96” (2438 mm)

0–100% economizer with return fan 72” (1829 mm) 96” (2438 mm)

Table 9: Outdoor/return air section

Outdoor/return air section 800C 802C

100% OA 0 0

Plenum 40” (1016 mm) 52" (1321 mm)

0–30% OA 40” (1016 mm) 52" (1321 mm)

0–100% economizer 40” (1016 mm) 52" (1321 mm) 0–100% economizer with 15" return fan 62" (1575 mm) — 0–100% economizer with 30" return fan 52" (1321 mm) 52" (1321 mm) 0–100% economizer with 40" return fan — 80" (2032 mm)

047C 077C

Table 10: “X” dimension (Figure 39 and Figure 40)

Outdoor/return air section

100 O.A. 00000000

Plenum 40 1016 52 1321 48 1259 72 1829

0–30% O.A. 40 1016 52 1321 48 1259 72 1829

0–100% economizer 40 1016 52 1321 72 1829 96 2438 0–100% economizer with 15” return fan 62 1575 — — — — — — 0–100% economizer with 30” return fan 52 1321 52 1321 — — — — 0–100% economizer with 40” return fan — — 80 2032 — — — —

0–100% economizer with return fan — — — — 72 1829 96 2438

015C–030C 036C–040C 045C–075C 080C–135C

in mm in mm in mm in mm

Table 11: “Y” dimension (Figure 39 and Figure 40)

RPS unit size Dimension “Y”

015C–030C 49.5" (1257 mm)

036C & 040C 38.2" (970 mm)

045C–090C 39.5" (1003 mm)

105C 30.5" (775 mm)

115C–135C 39.5‘” (1003 mm)

McQuay IM 738-2 35

Mechanical Installation

Figure 39: Unit type RPS/RDT lifting points Figure 40: Unit type RFS or RPS/RDT factory split at

condenser

4 L i f t i n g P o i n t s

Y = 0

36 McQuay IM 738-2

Mechanical Installation

(

)

Figure 41: Unit type RCS

4 L i f t i n g P o i n t s

Figure 43: RPS factory split at supply fan section

0 1 5 C - 0 3 0 C : A M i n . = 3 3 . 9 " ( 8 6 1 m m )

0 3 6 C & 0 4 0 C : A M i n . = 8 5 . 6 " ( 2 1 7 4 m m )

Figure 42: Unit type RCS or condenser section from RPS/ RDT factory split at condenser

0 4 5 C – 0 6 0 C : B ( mi n .) = 5 7 " ( 1 4 4 8 m m ) 0 7 0 C : B ( mi n .) = 9 3 " ( 2 3 6 2 m m )

C – 105

115C – 135C: B

min.) = 113" (2870 cm

045C–090C: B (Min.) = 72" (1829 mm) 105C–115C: B (Min.) = 96" (2438 mm) 125C–135C: B (Min.) = 120" (3048 mm)

McQuay IM 738-2 37

Mechanical Installation

Reassembly of Split Units

Although RoofPak units typically ship from the factory as complete units, they may be split at the factory in one of three possible configurations.

1 The RFS air handler section and RCS condenser section

ship as two separate units, each with its own power supply and unit nameplate. This configuration is ordered when the condenser is intended to remain remote from the air handler because of space or structural constraints.

On all units except the RFS with end discharge, refrigerant piping is stubbed out the exterior of the cabinet for convenient field piping between the RCS and RFS units, and all necessary refrigeration components are provided. Detailed instructions are on pages 47 to 52.

2 The RPS/RDT unit factory split at the condenser ships as

an air handler section and a condenser section that is recoupled together on the roof. This configuration is ordered if a packaged RPS unit is desired, but cannot go to the job site because of shipping length or weight limitations. A single nameplate is attached to the air handler section and power is fed to both sections through the main control box, as in a non-split RPS/RDT unit. Detailed instructions are on pages 42 to 46.

All interconnecting piping and refrigeration components are provided so that when the sections are coupled together, only field-provided couplings are required to connect the piping.

3 The RPS unit factory split at the fan ships as two pieces,

split at the supply fan bulkhead, to recouple together on the roof. Like the RPS/RDT unit factory split at the condenser, this configuration is ordered if shipping length or weight limitation prevents a packaged RPS/RDT from being ordered. Splitting at the fan has the advantage of leaving all factory refrigerant piping intact so field evacuation and charging is not required. Detailed instructions are on pages 38 to 41.

A single nameplate is attached to the air handler section and power is fed to both sections through the main control box, as in a non-split RPS/RDT unit.

RPS/RDT Factory Split at Fan

Field reassembly of an RPS/RDT unit that shipped split at the fan takes place in three phases: (1) setting the sections, (2) mechanically recoupling the cabinet, and (3) reconnecting power and control wiring.

Phase I. Set sections (Figure 44)

1 Remove top cap and save for Phase II, Step 1.

2 Remove screws on fan panel, leaving retainer clips in place

to secure bulkhead. Save screws for Phase II, Step 5.

3 Remove plywood and retaining angles from unit and

discard.

4 Carefully lower both sections of unit (fan end and

discharge end) into place, making sure the roof curb engages the recesses in the unit base.

38 McQuay IM 738-2

Figure 44: Set sections, Steps 1–4

Remove top cap and save for reassembly.

Mechanical Installation

Remove plywood and retaining angles from unit and discard.

Discharge end of unit

Fan end of unit

Remove screws on fan panel, leaving retainer clips in place. Save screws for reassembly.

McQuay IM 738-2 39

Mechanical Installation

Phase II. Reassemble cabinet (Figure 45)

1 Reinstall top cap removed in Phase I, Step 1.

2 Caulk (watertight) ends of splice cap.

3 Caulk (watertight) vertical seam.

4 Install #10 screws (provided).

5 Install screws (.25–20 ×.75) removed in Phase I, Step 2.

6 Install splice cover (provided).

Figure 45: Reassemble cabinet

Reinstall top cap saved in step 1

Caulk ends of splice cap

Splice cover, provided

See detail

Caulk vertical seam

Install screws (.25 to 20 × .75) saved from step 1

#10 screws, provided

Nut clip-on, provided

40 McQuay IM 738-2

Mechanical Installation

Phase III. Reconnect power and control wiring

The DX coil/condenser section contains power and control harnesses that have their excess length in the blank or heat section, which normally is immediately downstream of the fan. Once the sections are physically reconnected, the ends of the power harness are fed back through the unit base into the junction box, per the unit’s electrical schematics.

CAUTION

Connect the power block correctly and maintain proper phasing. Improper installation can cause severe equipment damage.

1 Make electrical connections and reinstall inner raceway

cover as shown in Figure 46.

Figure 46: Electrical connections and raceway cover installation

If applicable, install as shown with provided fasteners.

After routing wires, install inner raceway cover (see step 6).

3.72 ref. (94 mm)

When power wire reconnection is complete, reinstall the inner raceway cover in the blank or heat section. Figure 46 shows a typical installation of the raceway cover.

3 Run the control harnesses by removing the external

raceway covers on either side of the unit split.

4 Remove the excess harness length from the external

raceway on the DX side of the split; then route along the raceway, through the bushed hole in the fan section and into the junction box where control wiring terminal blocks are provided for reconnection.

5 Make all electrical connections per the unit’s electrical

schematics.

6 Reinstall the external raceway covers after routing of the

control wires is complete.

7 Draw through cooling coils only. Reconnect refrigerant

piping. These refrigerant circuits for these units are shipped with a holding charge only. Figure 47 illustrates what the installer sees at the shipping split

a To bridge the gap and connect the piping, remove the

refrigerant piping caps and add fittings and copper tubing, as required.

b Evacuate and charge the unit. See page 48 for further

details.

Figure 47: Refrigerant lines

Capped

refrigerant

lines

McQuay IM 738-2 41

Mechanical Installation

RPS/RDT Factory Split at Condensing Unit

3 Loosen piping brackets and clamps on both sections so

Field reassembly of an RPS/RDT unit that has shipped split at the condenser takes place in three phases: (1) setting the sections and mechanically recoupling the cabinet, (2) reconnecting refrigerant piping, and (3) reconnecting power and control wiring.

4 Physically rig the air handler section into place.

5 After air handler is installed, remove lifting bracket and

Phase I. Set sections and reassemble cabinet

1 Before setting sections together, remove top cap on air

handler section and wire cover on condensing section. See Figure 48. Discard wire cover.

2 Remove piping cover and discard. Reinstall screws in holes

to prevent water leakage.

Figure 48: RPS/RDT split at condensing unit reassembly, Steps 1–6

Step 3: Loosen piping clamps and move pipes

Step 1: Remove top cap and save for step 10.

RFS air

handler unit

to prevent piping interference during reassembly (suction, liquid, and hot gas bypass lines).

6 On condenser unit, remove bolts adjacent to lifting bracket

refrigerant lines can be moved out of the way to prevent interference and damage as the sections are set together. See Figure 48.

adjacent bolts on air handler unit (see Figure 48) and save for Step 7. Discard lifting bracket.

If unit is post-and-rail mounted on a structural beam that runs the full length of the unit, leave bolts and lifting brackets in place.

and save for Step 12.

RCS condensing unit

Step 2: Remove piping cover and discard. Reinstall screws to prevent water leakage.

Step 6: Remove bolt and save for step 7.

Step 5: After main unit is installed, remove lifting bracket on both sides and discard. Save bolts for ste

Note: RFS units with front discharge do NOT include refrigerant piping to the DX coil. Field piping is required.

7 Install condenser support on air handler unit as shown in

Figure 49. Fill unused holes in unit base with bolts saved in Step 6.

Step 1: Before units are assembled, remove wire cover and discard.

If unit is post-and-rail mounted on a structural beam that runs the full length of the unit, bolts and lifting brackets were not removed. Omit this step.

Step 6: Remove bolt and save for step 12.

42 McQuay IM 738-2

Mechanical Installation

Figure 49: Installing condenser support, Step 7

I n s t a l l c o n d e n s e r s u p p o r t o n m a i n u n i t a s s h o w n w i t h b o l t s s a v e d f r o m s t e p 1 ( t y p . b o t h s i d e s o f u n i t ) ; h o l e s i n u n i t b a s e w i t h b o l t s s a v e d f r o m S t e p 1 .

f i l l u n u s e d

Figure 50: Setting condenser unit in place, Steps 8 and 9

Step 8: Lower condenser unit until nearly level with main unit.

Lower the condenser unit until nearly level with main unit. See Figure 50.

9 Carefully shift condenser unit until it rests against the main

unit. See Figure 50.

CAUTION

Do not damage piping components while setting condensing unit in place.

CAUTION

Support condenser unit by crane during Step 9 since condenser support rail is not designed to withstand the heavy lateral forces of a unit being slid over it.

RFS unit

After condenser unit is set in place, install the top cap saved in Step 1. See Figure 51.

11 Caulk (watertight) ends of splice cap and vertical seam. See

Figure 51.

Step 9: Carefully shift condenser unit until it is resting against main unit.

CAUTION: Condenser support rail is not designed to withstand heavy lateral forces of unit being slid over it. During this step, support condensing unit with a crane.

Condenser support rail

12 Install 1/2" bolt removed in Step 5. See Figure 51.

13 Install splice cover (provided), see Figure 51.

McQuay IM 738-2 43

Mechanical Installation

Figure 51: Caulk and install parts, Steps 10–14

Reinstall top cap saved from Step 1

Caulk ends of splice cap

Reinstall 1/2" bolt saved from Ste

Phase II. Reconnect refrigerant piping

All refrigerant piping required to reconnect the two sections is provided so when the piping closures are cut off, piping from the air handler and condenser sections lines up.

1 Connect piping using field-supplied couplings.

2 As with RFS/RCS units, both sections of the RPS/RDT

split-at-condenser unit ship from the factory with a holding charge. Before removing the piping closures, inspect the unit for line breakage or loosening of fittings.

Nut clip-on provided

3 Perform pressure testing as described in the “Leak Testing”

section on page 47.

4 Perform evacuation, charging the system, and refrigerant

charge requirements for the split-at-condenser unit per procedures on page 47.

Note – Use Tables 15 to 18 on pages 49 to 50 to determine

refrigerant charge requirements for the RPS/RDT split-at-condenser. Because no field-installed refrigerant piping is required, the total charge per circuit is the sum of the base R-22 charge and the DX coil charge.

44 McQuay IM 738-2

Figure 52: RFS/RCS 015 to 030 refrigerant piping connections

L 1

L 2

H G 1

H G 2

L 2

S 2

S 1

S 2

H G 2

H G 1

Note: RFS units with front discharge do NOT include refrigerant piping to the DX coil. Field piping is required.

Figure 53: RFS/RCS 036 and 040 refrigerant piping connections

Mechanical Installation

S 1

L 1

L 2

H G 1

H G 2

L 2

S 2

S 1

H G 2

S 2

S 1

H G 1

L 1

Note: RFS units with front discharge do NOT include refrigerant piping to the DX coil. Field piping is required.

Table 12: Connection sizes and locations, Figures 52 and 53

Component circuit

015C 020C 025C

S1 Suction line Ckt.1 1 1/8 1 1/8 1 5/8 1 5/8 9.00 5.70 67.60 6.25 8.25 5.70 59.50 19.30 S2 Suction line Ckt.2 1 3/8 1 5/8 1 3/8 1 5/8 14.00 5.70 28.00 6.25 13.25 5.70 34.60 19.30 L1 Liquid line Ckt.1 5/8 5/8 7/8 7/8 56.00 32.00 75.00 6.25 79.00 25.00 70.50 25.00

L2 Liquid line Ckt.2 7/8 7/8 7/8 7/8 7.60 28.00 21.00 6.25 15.00 25.00 23.50 25.00 HG1 HGBP line Ckt.1 7/8 7/8 7/8 7/8 52.00 10.00 60.80 6.25 67.00 6.70 64.60 6.60 HG2 HGBP line Ckt.2 7/8 7/8 7/8 7/8 36.00 16.00 35.50 6.25 32.00 6.70 29.50 6.00

Connection sizes Connection locations

030Cto

040C

RFS 015 to 030 RCS 015 to 030 RFS 036 and 040 RCS 036 and 040 X (in.) Y (in.) X (in.) Y (in.) X (in.) Y (in.) X (in.) Y (in.)

McQuay IM 738-2 45

Mechanical Installation

Figure 54: RPS/RDT (split)/RFS/RCS 045 to 135 refrigerant piping connections

Note: RFS units with front discharge do NOT include refrigerant piping to the DX coil. Field piping is required.

Table 13: Connection sizes and locations, Figure 54

Connection sizes Connection locations

Component circuit

S1 Suction line Ckt.1 1 5/8 2 1/8 2 1/8 2 5/8 11.7 5.2 21. 7.0 5.7 11.7 S2 Suction line Ckt.2 1 5/8 2 1/8 2 1/8 2 5/8 7.5 5.2 16.5 7.0 5.7 7.5 L1 Liquid line Ckt.1 7/8 7/8 1-1/8 1 1/8 81.5 29.1 81.5 29.1 29.1 81.4

L2 Liquid line Ckt.2 7/8 7/8 1 1/8 1 1/8 10.3 29.1 10.3 29.1 29.1 10.4 HG1 HGBP line Ckt.1 7/8 7/8 7/8 7/8 52.1 10.4 52.1 10.4 10.4 52.1 HG2 HGBP line Ckt.2 7/8 7/8 7/8 7/8 40.9 4.7 40.9 4.7 4.7 40.9

045C

050C to

075C

Phase III. Reconnecting power and control wiring

The wire harnesses are coiled in the condenser section base rail (see Figure 55). The power wires into the lower base rail

080C to

90C

105C to

135C

air handler raceway and into the main control cabinet and plug into the plug patch panel.

Figure 55: Connecting power and control wiring (015 to 040)

RPS (split) and

RFS 045 to 075C

X (in.) Y (in.) X (in.) Y (in.) X (in.) Y (in.)

RCS 045 to 075C 080 to 135C

raceway and the control wires into the upper raceway.

1 Uncoil the harnesses and feed them through the base rail of

the air handler section and make the proper connections. The power wires terminate to the load side of the contactors; the control wires plug into the plug patch panel.

2 The liquid line solenoid valve harness is split into two

harnesses. Install one half in the plug patch panel in the main control box (see Figure 55).

3 The other half of the harness is located in conduit on the

bulkhead of the air handler section (see Figure 55).

4 Terminate the conduit to the vertical raceway in the

condenser section (see Figure 56).

5 Wire nut the ends of the two harnesses together.

6 The optional hot gas bypass solenoid valve harness is

coiled in the upper raceway of the condenser base rail (see Figure 56). Route the plug end of the harness through the

46 McQuay IM 738-2

Mechanical Installation

s c

Figure 56: Remove vertical raceway

R e m o v a b l e v e r t i c a l

A i r H a n d l e r

S e c t i o n

C o n d e n s e r S e c t i o n

R e m o v e

h i p p i n g o v e r

r a c e w a y s h i p s w i t h c o n d e n s e r s e c t i o n s

C o n t r o l w i r e s b u n d l e d a n d t a p e d i n s i d e t h i s r a c e w a y

P o w e r w i r e s b u n d l e d a n d t a p e d i n s i d e t h i s r a c e w a

RFS/RCS Permanent Split Systems

Piping Recommendations

1 Use type K or L clean copper tubing. Thoroughly clean or

braze all joints with high temperature solder. Make sure nitrogen is flowing through the tubes while brazing to minimize the formation of oxide contaminants.

2 Base piping sizes on temperature/pressure limitations as

recommended in the following paragraphs. Under no circumstances should pipe size be based strictly upon coil or condensing unit piping connection size.

3 Do not exceed suction line piping pressure drop equivalent

to 2°F (1°C), 3 psi (20.7 kPa) per 100 feet (30.5 m) of equivalent pipe length. After the suction line size is determined, check the vertical suction risers to verify that oil will be carried up the riser and back to the compressor. Pitch the suction line(s) in the direction of refrigerant flow and make sure they are adequately supported. Lines should be free draining and fully insulated between the evaporator and the compressor. Install a trap on the vertical riser to the compressor.

4 To determine the minimum tonnage required to carry oil up

suction risers of various sizes, check the vertical suction risers using Table 14.

Table 14: Minimum tonnage (R-22 or R-407C) to carry oil up suction riser at 40°F saturated suction

Line size O.D. Minimum tonnage

1 1/8" 1.5 1 3/8" 2.5 1 5/8" 3.8 2 1/8" 7.6 2 5/8" 13.10 3 1/8" 20.4 3 5/8" 29.7 4 1/8" 41.3

5 Size the liquid line for a pressure drop not to exceed the

pressure equivalent of 2°F (1°C), 6 psi (41.4 kPa) saturated temperature. The RFS unit includes a factory installed filter-drier, solenoid valve, and sightglass in each liquid line, upstream of the thermostatic expansion valve.

Holding Charge

The RFS unit and RCS unit ship with a nitrogen holding charge. At the time the unit is received, a visual inspection of the unit piping should be made to be sure no breakage occurred or that the fittings did not loosen during shipping. A pressure test on the RCS units should indicate a positive pressure in the unit. If no pressure is evident, the unit must be leak tested and the leak repaired. Note and report this to the McQuay sales representative and freight carrier (if the loss is due to shipping damage).

WARNING

Before applying heat to remove brazed piping caps and plugs, always vent piping to atmosphere. Failure to do so can cause hazardous pressures, explosion, severe personal injuries, or death.

RCS—Vent to atmosphere by opening gauge ports at the compressors and liquid line shutoff valves. Make sure manual valves are not back seated to shut off the gauge ports.

RFS—Vent to atmosphere by cutting off the process tubes on the suction line caps.

The RFS unit does not have gauge ports for pressure measurement. If no positive pressure is detected when cutting off the process tubes and removing the tubing caps, the unit should be leak tested as described below, after the interconnecting piping has been brazed in place. This test will also confirm the integrity of the field braze joints.

Leak Testing

In the case of loss of the nitrogen holding charge, the unit should be checked for leaks prior to charging the complete system. If the full charge was lost, leak testing can be done by charging the refrigerant into the unit to build the pressure to approximately 10 psig and adding sufficient dry nitrogen to bring the pressure to a maximum of 125 psig. The unit should then be leak tested with halide or electronic leak detector. After making any necessary repair, the system should be

evacuated as described in the following paragraphs.

WARNING

Do not use oxygen or air to build up pressure. Explosion hazard can cause severe personal injury or death.

McQuay IM 738-2 47

Mechanical Installation

Evacuation

After determining the unit is tight and there are no refrigerant leaks, evacuate the system. Use a vacuum pump with a pumping capacity of approximately 3 cu.ft./min. and the ability to reduce the vacuum in the unit to at least 1 mm (1000 microns).

1 Connect a mercury manometer or an electronic or other

type of micron gauge to the unit at a point remote from the vacuum pump. For readings below 1 millimeter, use an electronic or other micron gauge.

2 Use the triple evacuation method, which is particularly

helpful if the vacuum pump is unable to obtain the desired 1 mm of vacuum. The system is first evacuated to approximately 29" (740 mm) of mercury. Then add enough refrigerant vapor to the system to bring the pressure up to 0 pounds (0 microns).

3 Evacuate the system again to 29" (740 mm) of vacuum.

Repeat his procedure three times. This method is most effective by holding system pressure at 0 pounds (0 microns) for a minimum of 1 hour between evacuations. The first pulldown removes about 90% of the noncondensables; the second removes about 90% of that remaining from the first pulldown. After the third pulldown, only 1/10 of 1% of noncondensables remains.

Table 20 on page 51 shows the relationship between pressure, microns, atmospheres, and the boiling point of water.

CAUTION

Before replacing refrigerant sensors or protective devices, see “Refrigerant Charge” on page 52 for an important warning to prevent an abrupt loss of the entire charge.

CAUTION

To prevent liquid return and damage to the compressor on systems with optional hot gas bypass, locate the bypass solenoid valve on the RCS, not on the RFS unit.

CAUTION

To service liquid line components, the manual shutoff valve is closed and refrigerant is pumped into the condenser. The pounds of refrigerant in the system may exceed the capacity of the condenser, depending on the amount of refrigerant in the liquid lines between the RFS and RCS units. Suitable means of containing the refrigerant is required.

48 McQuay IM 738-2

Mechanical Installation

Table 15: Approximate R-22 refrigerant charge per circuit, 015 to 018, 020C to 040C

Base charge

Unit size

015 to 018 11 18 0.8/1.5 .5 1 47

020C 11 18 0.8/1.5 1 1 47 025C 23 22 1.7 1 1 72 030C 23 21 1.7 1 1 72 036C 32 32 1.7 1 1 106 040C 33 32 1.7 1 1 106

* Condenser pumpdown capacity is the total charge for both circuits and is based on volume between condenser entrance and liquid line

solenoid at 90°F, 90% full

lbs per circuit (less DX coil)

Circuit #1 Circuit #2 Circuit #1 Circuit #2

EVAP.coil

(lbs/CKT/coil row)

Additional charge for heat

section additional length

Condenser pumpdown

capacity*

(lbs)

Table 16: Approximate R-22 refrigerant charge per circuit, 045C to 135C

Base charge

Unit size

045C 34 33 34 28 2.5 — 108 050C 34 33 35 34 2.5 3.0 108 060C 35 34 35 34 2.5 3.0 108 070C 39 39 40 40 2.5 3.0 134 075C 39 39 40 40 2.5 3.0 134 080C 40 41 37 38 4.1 4.7 140 090C 46 47 44 47 4.1 4.7 160 105C 50 51 45 48 4.9 6.5 208 115C 59 60 60 63 4.9 6.5 208 125C — 60 — 65 — 6.5 208 135C — 60 — 65 — 6.5 208

* DX coil configuration (S = Standard, L = Large) is identified by the eighth digit of the RPS/RDT or RFS model number, found on the unit

nameplate. For example, DX = L for unit model number RFSO6OCLY.

** Condenser pumpdown capacity is the total charge for both circuits and is based on volume between condenser entrance and liquid line

solenoid at 90ºF, 90% full.

Circuit #1 Circuit #2 Circuit #1 Circuit #2

lbs per circuit (less DX coil)

RPS RDT

DX coil charge

lbs per circuit per coil row

DX=S* DX=L*

Condenser pumpdown

capacity**

(lbs)

Table 17: Approximate R-407C refrigerant charge per circuit, 015C to 040C

Unit size

015C to 018C 10 16 0.7/1.4 .5 1 45

020C 10 16 0.7/1.4 1 1 45 025C 21 20 1.6 1 1 68 030C 21 19 1.6 1 1 68 036C 29 29 1.6 1 1 101 040C 30 29 1.6 1 1 101

* Condenser pumpdown capacity is the total charge for both circuits and is based on volume between condenser entrance and liquid line

solenoid at 90°F, 90% full

Base charge

lbs per circuit (less DX coil)

Circuit 1 Circuit 2 Circuit 1 Circuit 2

Evaporator coil

(lbs/CKT/coil row)

Additional charge for heat

section additional length

Condenser pumpdown

capacity* (lbs)

McQuay IM 738-2 49

Mechanical Installation

Table 18: Approximate R-407C refrigerant charge per circuit, 045C to 135C

Base charge

Unit size

045C 31 30 31 26 2.3 — 103 050C 31 30 32 31 2.3 2.8 103 060C 32 31 32 31 2.3 2.8 103 070C 36 36 37 37 2.3 2.8 127 075C 36 36 37 37 2.3 2.8 127 080C 37 37 34 35 3.8 4.3 134 090C 42 43 41 43 3.8 4.3 152 105C 46 42 41 44 4.5 6.0 198 115C 54 55 55 58 4.5 6.0 198 125C — 55 — 60 — 6.0 198 135C — 55 — 60 — 6.0 198

* DX coil configuration (S = Standard, L = Large) is identified by the eighth digit of the RPS/RDT or RFS model number, found on the unit

nameplate. For example, DX = L for unit model number RFSO6OCLY.

* Condenser pumpdown capacity is the total charge for both circuits and is based on volume between condenser entrance and liquid line

solenoid at 90ºF, 90% full.

Circuit #1 Circuit #2 Circuit #1 Circuit #2

lbs per circuit (less DX coil)

RPS RDT

DX coil charge

lbs per circuit per coil row

DX=S* DX=L*

Condenser pumpdown

capacity**

(lbs)

Table 19: Weight of refrigerant in copper lines (pounds per 100 feet of Type L tubing)

O.D. line size

3/8" 0.054 3.84 3.64 0.20 0.46 0.052 0.047 0.077 0.071 1/2" 0.100 7.12 6.74 0.37 0.85 0.096 0.088 0.143 0.132 5/8" 0.162 11.53 10.92 0.61 1.38 0.156 0.142 0.232 0.214

7/8" 0.336 23.92 22.65 1.26 2.87 0.324 0.294 0.480 0.444 1 1/8" 0.573 40.80 38.62 2.14 4.89 0.552 0.501 0.819 0.756 1 3/8" 0.872 62.09 58.77 3.26 7.44 0.840 0.763 1.247 1.151 1 5/8" 1.237 88.07 83.37 4.63 10.55 1.191 1.082 1.769 1.633 2 1/8" 2.147 152.87 144.71 8.03 18.31 2.068 1.879 3.070 2.834 2 5/8" 3.312 235.81 223.23 12.38 28.25 3.189 2.898 4.736 4.372 3 1/8" 4.728 336.63 318.67 17.68 40.33 4.553 4.137 6.761 6.241 3 5/8” 6.398 455.54 431.23 23.92 54.57 6.161 5.598 9.149 8.445 4 1/8" 8.313 591.89 560.30 31.08 70.91 8.005 7.274 11.888 10.973

Vol. per 100 ft

in cubic feet

Liquid @100°F Hot gas@120°F cond. Suction gas (superheat to 85°F)

R-22 R-407C R-22 R-407C

Weight of refrigerant, lbs./100 feet

30°F 40°F

R-22 R-407C R-22 R-407C

50 McQuay IM 738-2

Table 20: Pressure-vacuum equivalents

Absolute pressure above zero Vacuum below 1 atmosphere

Microns PSIA Mercury (mm) Mercury (in)

0 0 760.00 29.921 — —

50 0.001 759.95 29,920 1/15,200 –50

100 0.002 759.90 29.920 1/7,600 –40

150 0.003 759.85 29.920 1/5,100 –33

200 0.004 759.80 29.910 1/3,800 –28

300 0.006 759.70 29.910 1/2,500 –21

500 0.009 759.50 29.900 1/1,520 –12

1,000 0.019 759.00 29.880 1/760 1

2000 0.039 758.00 29.840 1/380 15

4,000 0.078 756.00 29.760 1/189 29

6000 0.117 754.00 29.690 1/127 39

8,000 0.156 752.00 29.600 1/95 46

10,000 0.193 750.00 29.530 1/76 52

15,000 0.290 745.00 29.330 1/50 63

20,000 0.387 740.00 29.130 1/38 72

30,000 0.580 730.00 28.740 1/25 84

50,000 0.967 710.00 27.950 1/15 101

100,000 1.930 660.00 25.980 2/15 125

200,000 3.870 560.00 22.050 1/4 152

500,000 9.670 260.00 10.240 2/3 192

760,000 14.697 0 0 1 atmosphere 212

Approximate fraction

of 1 atmosphere

H2O boiling point at each

Mechanical Installation

pressure (

Charging the System

RCS units are leak tested at the factory and shipped with a nitrogen holding charge. If the holding charge has been lost due to shipping damage, charge the system with enough refrigerant to raise the unit pressure to 30 psig after first repairing the leaks and evacuating the system.

1 After all refrigerant piping is complete and the system is

evacuated, it can be charged as described in the paragraphs following. Connect the refrigerant drum to the gauge port on the liquid shutoff valve and purge the charging line between the refrigerant cylinder and the valve. Then open the valve to the mid position.

2 If the system is under a vacuum, stand the refrigerant drum

with the connection up, open the drum, and break the vacuum with refrigerant gas.

3 With a system gas pressure higher than the equivalent of a

freezing temperature, invert the charging cylinder and elevate the drum above the condenser. With the drum in this position and the valves open, liquid refrigerant flows into the condenser. Approximately 75% of the total requirement estimated for the unit can be charged in this manner.

4 Refrigerant charging with Zeotropes—R-407C is a

zeotropic mixture (see “Refrigerant Leaks” on page 131). During initial charging or “topping” off a system, it is important to remove the refrigerant from the charging cylinder in the liquid phase. Many of the cylinders for the newer refrigerants use a dip tube so that in the upright position liquid is drawn from the cylinder. DO NOT vapor charge out of a cylinder unless the entire cylinder is to be charged into the system. Refer to charging instructions provided by the refrigerant manufacturer.

5 After 75% of the required charge enters the condenser,

reconnect the refrigerant drum and charging line to the suction side of the system. Again, purge the connecting line, stand the drum with the connection side up, and place the service valve in the open position.

Note – Stamp the total operating charge per circuit on the unit

nameplate for future reference.

CAUTION

Adding refrigerant to the suction always risks liquid-related damage to the compressor.

McQuay IM 738-2 51

Mechanical Installation

Take special care to add refrigerant slowly enough to the suction to prevent damage. Adjust the charging tank hand valve so liquid leaves the tank but vapor enters the compressor.

This is especially true with R-407C because the charge must be drawn from the liquid portion of the tank.

CAUTION

Units purchased for R-22 operation must be charged only with R-22. Units purchased for R-407C operation must be charged only with R-407C.

Field mixing or changing of refrigerants can compromise performance and damage equipment.

Table 21: Acceptable refrigerant oils

R-22 (mineral oils)

Note: Do not use mixtures of

mineral oils and POE oils with R-

22.

Sunisco 3GS Copeland ULtra 22 CC

Texaco WF32 Mobil EAL™ Arctic 22 CC

Calumet R015 ICI EMKARATE RL™ 32CL

R-407C (polyolester [POE] oils)

Note: Do not use mineral oils

with R-407C

Refrigerant Charge

Each unit is designed for use with R-22 or R-407C. The total charge per circuit is the sum of the following four values:

• Condenser section charge, see Table 15 on page 49.

• Evaporator coil charge, see Table 15 on page 49.

• Charge for length of unit piping to the evaporator coil, see

Table 15 on page 49.

• Charge for length of interconnecting piping between the RCS and RFS units, installed by field, see Table 19 on page 50.

The exact charge for a one piece RPS/RDT is on the unit nameplate.

Note – The total operating charge per circuit should not exceed

the pumpdown capacity per circuit shown in Tables 15 to 19 on pages 49 to 50.

Subcooling

When field charging the unit, use the following to properly charge the unit:

• All compressors on each circuit operating at full capacity.

• Allowable subcooling ranges are between 13°F to 20°F.

• Be sure to measure pressure and temperature at the same

location when finding/calculating subcooling. Compare the actual temperature and pressures to the saturated liquid temperature. R-407C example: A pressure of 250 psi is measured at the condenser outlet. From the R-407C chart, 250 psig is approximately 108°F saturated liquid temperature. If the actual refrigerant temperature is 98°F, the liquid is subcooled 10°F.

• Ambient temperature must be between 60°F and 105°F.

• Hot Gas Bypass NOT operating (only if unit is supplied with

option).

• SpeedTrol motors operating at 100% (only if unit is supplied with option).

If any one of the above items is not followed, subcooling readings will not be accurate and the potential exists for over or undercharging of the refrigerant circuit.

Refrigeration Service Valves

The unit is shipped with all refrigeration service valves closed. RDT, RPS and RCS units have the following:

Sizes 15 to 105—One discharge valve is provided per refrigerant circuit, located between the compressors and condenser.

Sizes 115 to 135—One service valve is provided on the discharge and suction of each compressor.

All Units—One liquid valve is provided per refrigeration circuit, located at end of condensing section opposite condenser control box.

RFS units do not ship with service valves installed. Before attempting to start the compressors, all refrigeration service valves should be fully opened and backseated.

Unit Piping

Condensate Drain Connection

• The unit is provided with a 1.5" male NPT condensate drain connection. Refer to certified drawings for the exact location. For proper drainage, level the unit and drain pan side to side and install a P-trap

• RPS units may have positive or negative pressure sections. Use traps in both cases with extra care given to negative pressure sections. In Figure 57, dimension “A” should be a minimum of 8" (203 mm). As a conservative measure to prevent the cabinet static pressure from blowing or drawing the water out of the trap and causing air leakage, dimension A should be two times the maximum static pressure encountered in the coil section in inches wc.

• Draining condensate directly onto the roof may be acceptable; refer to local codes. Provide a small drip pad of stone, mortar, wood, or metal to protect the roof against possible damage.

• If condensate is piped into the building drainage system, pitch the drain line away from the unit a minimum of 1/8" per foot. The drain line must penetrate the roof external to the unit. Refer to local codes for additional requirements. Sealed drain lines require venting to provide proper condensate flow.

• Where the cooling coils have intermediate condensate pans on the face of the evaporator coil, copper tubes near both ends of the coil provide drainage to the main drain pan.

52 McQuay IM 738-2

Mechanical Installation

Check that the copper tubes are in place and open before the unit is put into operation.

• On units with staggered cooling coils, the upper drain pan drains into the lower coil drain pan through a copper tube near the center of the drain pan. Check that this tube is open before putting the unit into operation and as a part of routine maintenance.

• Because drain pans in any air conditioning unit have some moisture in them, algae, etc. will grow. Periodically clean to prevent this buildup from plugging the drain and causing the drain pan to overflow. Clean drain pans to prevent the spread of disease. Cleaning should be performed by qualified

personnel

WARNING

Drain pans must be cleaned periodically.

Material in uncleaned drain pans can cause disease.

Cleaning should be performed by qualified personnel.

Figure 57: Condensate drain connection

can guarantee a 100% safeguard against coil freeze-up. Glycol solutions or brines are the only freeze-safe media for operation of water coils at low entering air temperature conditions.

When no factory piping or valve is included, the coil connections are 1.625” ODM copper on 800 and 802C, and

2.125" ODM copper on 047 and 077C.

With the factory piping and valve package, field piping connections are the same NPT size as the valve with female threading (see Figure 59 on page 53).

Refer to the certified drawings for the recommended piping entrance locations. Seal all piping penetrations to prevent air and water leakage.

Note – Factory-installed water valves and piping are bronze,

brass, and copper. Dissimilar metals within the plumbing system can cause galvanic corrosion. To avoid corrosion, provide proper di-electric fittings as well as appropriate water treatment.

Figure 58: Hot water heat section (shown with factory valve and piping)

S e e V i e w " A "

C o p p e r T u b e

( o n e e a c h e n d o f c o i l )

S t a t i c P r e s s u r e " P "

4 " ( 1 0 2 m m )

M i n i m u m

" A "

8 " ( 2 0 3 m m )

M i n . o r 2 x " P "

( i n . w . o . )

D r a i n P a n

V i e w A

N o t e : D r a i n l i n e m u s t

n o t b e r u n h i g h e r

t h a n t h i s l e v e l

M i n i m i z e T h i s

e n s i o n

D i m

Gas Piping

See the “Installation” section of the gas-fired furnace installation manual, Bulletin No. IM 684 or 685.

Hot Water Coil Piping

Hot water coils are provided without valves for field piping or piped with three-way valves and actuator motors.

Note – All coils have vents and drains factory installed.

Hot water coils are not normally recommended for use with entering air temperatures below 40°F (4°C). No control system

Figure 59: Hot water valve package

R e t u r n

B y p a s s

S u p p l y

CAUTION

Coil freeze possible. Can damage equipment. Follow instructions for mixing antifreeze solution used. Some products have higher freezing points in their natural state than when mixed with water. The freezing of coils is not the responsibility of McQuay International. Refer to “” on page 131.

McQuay IM 738-2 53

Mechanical Installation

Steam Coil Piping

Steam coils are provided without valves for field piping, or piped with two-way valves and actuator motors.

The steam heat coil is pitched at 1/8" (3 mm) per foot (305 mm) to provide positive condensate removal. When no factory piping or valve is included, the coil connections are 2.5" male NPT iron pipe.

With the factory piping and valve package, the field supply connection is the same NPT size as the valve with female threading (see Figure 62 on page 55).

Refer to the certified drawings for the recommended piping entrance locations. All piping penetrations must be sealed to prevent air and water leakage.

Note – The valve actuator spring returns to a stem up position

upon power failure. This allows full flow through the coil.

Figure 60: Steam heat section (shown with factory valve and piping)

Steam Piping Recommendations

1 Be certain that adequate piping flexibility is provided.

Stresses resulting from expansion of closely coupled piping and coil arrangement can cause serious damage.

2 Do not reduce pipe size at the coil return connection. Carry

return connection size through the dirt pocket, making the reduction at the branch leading to the trap.

3 Install vacuum breakers on all applications to prevent

retaining condensate in the coil. Generally, the vacuum breaker is to be connected between the coil inlet and the return main. However, if the system has a flooded return main, the vacuum breaker to the atmosphere; the trap design should allow venting of the large quantities of air.

4 Do not drain steam mains or takeoffs through coils. Drain

mains ahead of coils through a steam trap to the return line.

5 Do not attempt to lift condensate.

6 Pitch all supply and return steam piping down a minimum

of 1" (25 mm) per 10 feet (3 m) of direction of flow.

54 McQuay IM 738-2

Mechanical Installation

Steam Trap Recommendations

1 Size traps in accordance with manufacturers’

recommendations. Be certain that the required pressure differential will always be available. Do not undersize.

2 Float and thermostatic or bucket traps are recommended for

low pressure steam. Use bucket traps on systems with onoff control only.

3 Locate traps at least 12" (305 mm) below the coil return

connection.

4 Always install strainers as close as possible to the inlet side

of the trap.

5 A single tap may generally be used for coils piped in

parallel, but an individual trap for each coil is preferred.

Steam Coil Freeze Conditions

If the air entering the steam coil is below 35°F (2°C), note the following recommendations:

1 Supply 5 psi (34.5 kPa) steam to coils at all times.

2 Modulating valves are not recommended. Control should

be by means of face and bypass dampers.

3 As additional protection against freeze-up, install the tap

sufficiently far below the coil to provide an adequate hydrostatic head to ensure removal of condensate during an interruption on the steam pressure. Estimate 3 ft. (914 mm) for each 1 psi (7 kPa) of trap differential required.

4 If the unit is to be operated in environments with possible

freezing temperatures, an optional freezestat is recommended. See “Freeze Protection” on page 100 for additional information.

Figure 61: Valve assembly

S t e m C l i p

S t e m

Figure 62: Steam valve package

S e t s c r e w s

McQuay IM 738-2 55

Mechanical Installation

Damper Assemblies

The optional damper assemblies described in this section normally are ordered with factory-installed actuators and linkages. The following sections describe operation and linkage adjustment of the factory option.

Economizer Dampers

Outside air intake is provided on both sides of the unit, and the return air path is at the center of the damper set. As the single actuator modulates the outside air dampers open, the return air dampers close. Exhaust air exits the unit through the gravity relief dampers provided at the end of the economizer section.

The damper is set so that the crankarm moves through a 90degree angle to bring the economizer dampers from full open to full close (see Figure 63). Access to the actuator and linkage is from the filler section. Mechanical stops are placed in the crankarm mounting bracket. Do not remove stops. Driving the crankarm past the stops results in damage to the linkage or damper. The unit ships with a shipping bolt securing the linkage crankarm. Remove shipping bolt before use.

Figure 63: Damper adjustment

Note – For good airflow control, adjust linkages so damper

56 McQuay IM 738-2

blades do not open beyond 70 degrees. Opening a damper blade beyond 70 degrees has little effect on its airflow. Do not “over close” low leak damper blades. The edge seal should just lightly contact the adjoining blade. The blades will lock up if they are closed so far the seal goes over center.

Mechanical Installation

Intake Hood Damper (0% to 100% outside air)

Units requiring 100% outside air are provided with a rain hood and dampers that can be controlled by a single actuator. The actuator provides two-position control for opening the dampers fully during unit operation and closing the dampers during the off cycle. No unit mounted exhaust dampers are provided.

Intake Hood Damper (0% to 30% outside air)

These dampers are intended to remain at a fixed position during unit operation, providing fresh air quantities from 0 to 30% of the total system airflow, depending on the damper setting. This setting is made at the linkage rod on units with manually adjustable linkages.

On units provided with MicroTech II controls, the damper position may be set at the controller keypad. During unit operation, the two-position actuator drives the damper to the position set on the keypad. During the off cycle, the damper is automatically closed.

No unit-mounted exhaust dampers are provided with this option.

Figure 64: Damper linkage bar typical for all sizes, sizes 15C to 40C shown

Figure 65: Intake hood damper adj.

Airflow

A i r f l o w

3 . 1 5 " ( 8 0 m m ) M a x . S t r o k e o f D a m p e r L i n k a g e B a r

Note –

closed

90

stroke

open

.25" (6mm)

McQuay IM 738-2 57

Mechanical Installation

Cabinet Weather Protection

This unit ships from the factory with fully gasketed access doors and cabinet caulking to provide weather resistant operation. After the unit is set in place, inspect all door gaskets for shipping damage and replace if necessary.

Protect the unit from overhead runoff from overhangs or other such structures.

Recaulk field-assembled options such as external piping or vestibules per the installation instructions provided with the option.

CAUTION

Transportation, rigging, or maintenance can damage the unit’s weather seal. Periodically inspect the unit for leakage. Standing moisture can promote microbial growth, disease, or damage to the equipment and building.

Installing Ductwork

On bottom-supply/bottom-return units, if a McQuay roof curb is not used, the installing contractor should make an airtight connection by attaching field-fabricated duct collars to the bottom surface of either the roof curb’s duct flange or the unit’s duct opening. Do not support the total weight of the duct work from the unit or these duct flanges. See Figure 66.

expose the discharge duct collars on a side discharge unit, remove the plenum section access door and the door gasketing.

Use flexible connections between the unit and ductwork to avoid transmission of vibration from the unit to the structure.

To minimize losses and sound transmission, design duct work per ASHRAE and SMACNA recommendations.

Where return air ducts are not required, connect a sound-absorbing T or L section to the unit return to reduce noise transmission to the occupied space.

WARNING

Mold can cause personal injury. Materials such as gypsum wall board can promote mold growth when damp. Such materials must be protected from moisture that can enter units during maintenance or normal operation.

Ductwork exposed to outdoor conditions must be built in accordance with ASHRAE and SMACNA recommendations

and local building codes

NOTICE

Installer must provide access in the ductwork for plenum-mounted controls. Once duct work is installed in units with side discharge, access to plenum-mounted components is difficult.

Units with optional back return, side discharge, or end discharge (on RFS units), all have duct collars provided. To

Figure 66: Installing duct work

U n i t D u c t O p e n i n g

9 . 7 6 "

4 . 5 8 "

F l e x i b l e

C o n n e c t o r

D u c t w o r k

D u c t F l a n g e r i n R o o f C u r b

U n i t B a s e

R o o f C u r b

58 McQuay IM 738-2

Mechanical Installation

Installing Duct Static Pressure Sensor Taps

For all VAV units, field install and connect duct static pressure taps to the pressure sensors in the unit. Sensor SPS1 is standard; additional sensor SPS2 is optional. These sensors are located in the main control panel (see “Control Panel” on page

14).

Carefully locate and install the duct static pressure sensing tap. Improperly locating or installing the sensing tap causes unsatisfactory operation of the entire variable air volume system. Below are pressure tap location and installation recommendations. The installation must comply with local code requirements

1 Install a tee fitting with a leak-tight removable cap in each

tube near the sensor fitting. This facilitates connecting a manometer or pressure gauge if testing is required.

2 Use different colored tubing for the duct pressure (HI) and

reference pressure (LO) taps, or tag the tubes. McQuay recommends 1/4" plastic tubing.

3 Locate the duct pressure (HI) tap near the end of a long

duct to ensure that all terminal box take-offs along the run have adequate static pressure.

4 Locate the duct tap in a nonturbulent flow area of the duct.

Keep it several duct diameters away from take-off points, bends, neckdowns, attenuators, vanes, or other irregularities.

5 Use a static pressure tip (Dwyer A302 or equivalent) or the

bare end of the plastic tubing for the duct tap. (If the duct is lined inside, use a static pressure tip device.)

6 Install the duct tap so that it senses only static pressure (not

velocity pressure). If a bare tube end is used, it must be smooth, square (not cut at an angle) and perpendicular to the airstream (see Figure 68).

7 Locate the reference pressure (LO) tap somewhere near the

duct pressure tap within the building (see Figure 67). If the reference tap is not connected to the sensor, unsatisfactory operation will result.

8 Route the tubes between the curb and the supply duct, and

feed them into the unit through the knockout in the bottom of the control panel (see Figure 67). Connect the tubes to appropriate barbed fittings in the control panel. (Fittings are sized to accept 1/4" plastic tubing.)

Figure 67: Static pressure tubing entrance location

Static pressure

tubing

Figure 68: Pressure sensing tubing installation

Main Control Panel

"HI line"

"LO" line

Remote Sense Point

To Sensor "HI" input

Ductwork

(Remote Locat ion)

SPS1

Rubber Grommet

Roof

Tubing Extends thru Approx. 1/8"

To Sensor "LO" Input

Pressure Sensing Tubing

McQuay IM 738-2 59

Mechanical Installation

Installing Building Static Pressure Sensor Taps

If a unit has direct building static pressure control capability, you must field install and connect static pressure taps to pressure sensor SPS2 in the unit. This sensor is located at the bottom of the main control panel next to terminal block TB2.

Carefully locate and install the two static pressure sensing taps. Improper location or installation of the sensor taps causes unsatisfactory operation. Below are pressure tap location and installation recommendations for both building envelope and lab, or “space within a space” pressure control applications.

The installation must comply with local code requirements.

CAUTION

Fragile sensor fittings. If you must remove tubing from a pressure sensor fitting, use care. Do not use excessive force or wrench the tubing back and forth to remove; the fitting can break off and damage sensor.

Building Pressurization Applications

1 Install a tee fitting with a leak-tight removable cap in each

tube near the sensor fitting. This facilitates connecting a manometer or pressure gauge if testing is required.

2 Locate the building pressure (HI) tap in the area that

requires the closest control. Typically, this is a ground level floor that has doors to the outside.

3 Locate the building tap so it is not influenced by any source

of moving air (velocity pressure). These sources may include air diffusers or outside doors.

4 Route the building tap tube between the curb and the

supply duct and feed it into the unit through the knockout in the bottom of the control panel (see Figure 67). Connect the tube to the 1/4-inch HI fitting for sensor SPS2.

5 Locate the reference pressure (LO) tap on the roof. Keep it

away from the condenser fans, walls, or anything else that may cause air turbulence. Mount it high enough above the roof so it is not affected by snow. Not connecting the reference tap to the sensor results in unsatisfactory operation.

6 Use an outdoor static pressure tip (Dwyer A306 or

equivalent) to minimize the adverse effects of wind. Place some type of screen over the sensor to keep out insects. Loosely packed cotton works well.

7 Route the outdoor tap tube out of the main control panel

through a small field-cut opening in the edge of the control wiring raceway cover (see Figure 67 on page 59). Cut this “mouse hole” in the vertical portion of the edge. Seal the penetration to prevent water from entering. Connect tube to the 1/4-inch LO fitting for sensor SPS2.

Lab Pressurization Applications

1 Install a “T” fitting with a leak-tight removable cap in each

tube near the sensor fitting. This facilitates connecting a manometer or pressure gauge if testing is required.

2 Use different colored tubing for the controlled space

pressure (HI) and reference pressure (LO) taps, or tag the tubes.

3 Regardless whether the controlled space is positive or

negative with respect to its reference, locate the HI pressure tap in the controlled space (the setpoint can be set between –0.2 and 0.2" wc).

4 Locate the reference pressure (LO) tap in the area

surrounding the controlled space. Not locating the reference tap to the sensor results in unsatisfactory operation.

5 Locate both taps so they are not influenced by any source

of moving air (velocity pressure). These sources may include air diffusers or doors between the high and low pressure areas.

6 Route the building tap tube between the curb and the

supply duct and feed it into the unit through the knockout in the bottom of the control panel (see Figure 67).

7 Connect the tube to the 1/4-inch HI fitting for sensor SPS2.

60 McQuay IM 738-2

Electrical Installation

Field Power Wiring

Wiring must comply with all applicable codes and ordinances. The warranty is voided if wiring is not in accordance with these specifications. An open fuse, tripped circuit breaker, or Manual Motor Protector (MMP) indicates a short, ground, or overload. Before replacing a fuse, circuit breaker, MMP, or restarting a compressor or fan motor, identify the trouble and correct.

According to the National Electrical Code, a disconnecting means shall be located within sight of and readily accessible from the air conditioning equipment. The unit can be ordered with an optional factory mounted disconnect switch. This switch is not fused. Power leads must be over-current protected at the point of distribution. The maximum allowable overcurrent protection (MROPD) appears on the unit nameplate.

All RPS, RFS, and RDT

All units are provided with internal power wiring for single or dual point power connection. The power block or an optional disconnect switch is located within the main control panel. Field power leads are brought into the unit through 3" knockouts in the bottom of the main control panel. Refer to the unit nameplate to determine the number of power connections. See Figure 69 and Table 23 on page 63.

WARNING

Hazardous voltage. Can cause severe injury or death. Disconnect electric power before servicing equipment. More than one disconnect may be required to de-energize the unit.

If the unit has a factory mounted disconnect switch, generally the switch must be turned off to open the main control panel door. However, the door can be opened without disconnecting power by following the procedure covered on page 133. If this is done, use caution since power is not removed from the unit or the controller.

Note – To wire entry points, refer to certified drawings for

dimensions.

Figure 69: RPS/RDT and RFS power wiring connections

Electric heat control panel

Optional

disconnect

(DS3)

3" power

knockouts

Optional

disconnect (DS2)

Main disconnect (DS1)

or power block (PB1)

3" power

knockouts

Figure 70: Optional side power wiring entrance

3 " ( 7 6 m m )

M a x D i a .

M a i n C o n t r o l P a n e l

R e m o v e L i f t i n g B r a c k e t ( I f L o c a t e d H e r e ) B e f o r e D r i l l i n

2 . 7 5 " ( 7 0 m m )

H o l e

1 6 "

( 4 0 6 m m )

• The preferred entrance for power cables is through the bottom knockouts provided on the unit. If side entrance is

the only option, a drilling location is provided.

CAUTION

Wires are located in base rail. Move wires before drilling hole through base rail.

Follow the drilling dimensions exactly to prevent damage to the control panel. The dimensions provided are the only possible point of side entrance for the power cables.

RCS Units

Field power wiring is connected from the main control panel in the RFS unit to powerblock (PB4) or an optional disconnect switch (DS4) located in the condenser control panel of the RCS unit. Power leads enter the bottom left corner of the

McQuay IM 738-2 61

Electrical Installation

condenser control panel through the conduit hubs shipped with the unit. Refer to Figure 72 and Figure 73 on page 63.

Figure 71: Typical power wire entrance, unit view—RPS 015C to 040C shown (actual opening shown on submittal documents)

20.0

10.0

6.0

76.0

3.8

86.5

94.0

3.8

Supply air opening

10.0

1.50 MPT drain

Detail B

3.8

0.9 Dia. K.O. (Qty 4)

Bottom ret urn opening

24.3

Va r ie s

based on

options

17.7

22.3

12.9

15.3

3.0 Dia. K.O. (Qty 3)

6.8

11. 9

12.0

Reference from leaving air end of section

8.8

7.6

6.6

3.8

All Units

The minimum circuit ampacity (wire sizing amps) is shown on the unit nameplate. Refer to Table 23 on page 63 for the recommended number of power wires.

Copper wire is required for all conductors. Size wires in accordance with the ampacity tables in Article 310 of the National Electrical Code. If long wires are required, it may be necessary to increase the wire size to prevent excessive voltage drop. Size wires for a maximum of 3% voltage drop. Supply voltage must not vary by more than 10% of nameplate. Phase voltage imbalance must not exceed 2%. (Calculate the average voltage of the three legs. The leg with voltage deviating the

farthest from the average value must not be more than 2% away.) Contact the local power company for correction of improper voltage or phase imbalance.

CAUTION

Provide proper line voltage and phase balance. Improper line voltage or excessive phase imbalance constitutes product abuse. It can cause severe damage to the unit's electrical components.

A ground lug is provided in the control panel for each disconnect or power block. Size grounding conductor in accordance with Table 250-95 of the National Electrical Code.

62 McQuay IM 738-2

In compliance with the National Electrical Code, an

electrically isolated 115V circuit is provided in the unit to supply the factory mounted service receptacle outlet and optional unit lights. This circuit is powered by a field connected 15A, 115V power supply. Leads are brought into the RFS and RPS units through a 7/8" knockout in the bottom of the main control panel, near the power wire entry point.

Figure 72: RCS 015C–030C power wiring connections

Conduit and hub (shipped with RCS unit)

Power block PB4

or disconnect

switch DS4

7/8" knockout for

wire entry (field to cut

larger holes as required

for power wire)

Terminal block TB8 for 115V service receptical circuit

Figure 73: RCS 036C and 135C power wiring connections (number of condenser fans varies per unit size)

Conduit and hub

(shipped with RCS unit)

Power block PB4 or

disconnect switch DS4

7/8" knockout for TB8 wire entry

7/8" knockout fo TB8 wire entry

Terminal aTB8 for 115V service

7/8" knockout for wire entry (field to cut larger holes as required for pwer wire)

receptical circuit

Electrical Installation

Table 22: Multiple point power connection options

Number of

electrical

circuits

Disconnect designation

DS2

Load

Supply and return fan

motors plus controls

DS1 Balance of unit Main control panel

DS3 Electric heat

DS1 Balance of unit Main control panel

DS3 Electric heat

DS2

Supply and return fan

motors plus controls

DS1 Balance of unit Main control panel

Location

(see Figure 3 on

page 6)

Main control panel

Electric heat control panel

Main control panel

Table 23: Recommended 3-phase power wiring to ensure disconnects and power blocks mate with power wiring

Wire

gauge

Qty./

pole

Insulation

rating

(°C)

No. of

conduits

Conduit

(trade size, in.)

10 1 75 1 1/2 35

8 1 75 1 3/4 50 6 1 75 1 1 65 41 75 1 1 1/4 85 3 1 75 1 1 1/4 100 2 1 75 1 1 1/4 115

1 1 75 1 1 1/4 130 1/0 1 75 1 1 1/2 150 2/0 1 75 1 2 175 3/0 1 75 1 2 200 4/0 1 75 1 2 230

250 1 75 1 2 1/2 255 300 1 75 1 2 1/2 285 350 1 75 1 3 310 400 1 75 1 3 335 500 1 75 1 3 380

3/0 2 75 2 2 400 4/0 2 75 2 2 460

250 2 75 2 2 1/2 510 300 2 75 2 2 1/2 570 350 2 75 2 3 620 400 2 75 2 3 670 500 2 75 2 3 760 250 3 75 3 2 1/2 765 300 3 75 3 2 1/2 855 350 3 75 3 3 930

1.All wire sizes assume separate conduit for each set of parallel conductors.

2.All wire sizes based on NEC Table 310-16 for 75°C THW wire (copper). Canadian electrical code wire ampacities may vary.

3.All wire sizes assume no voltage drop for short power leads.

For MCA

up to

(amps)

McQuay IM 738-2 63

Electrical Installation

Field Control Wiring

Roof Pak applied rooftop units are available with several control arrangements which may require low voltage field wiring. Detailed descriptions of various field control wiring options and requirements are included in the “Field Wiring” section of Bulletin No. IM 696, “MicroTech II Applied Rooftop Unit Controller.” Refer to the unit wiring diagrams for additional installation information.

Wiring must comply with applicable codes and ordinances. The warranty is voided if wiring is not in accordance with these specifications.

RPS, RDT, and RFS Units

All field control wiring connections are made at the class II terminal block TB2, which is located in the main control panel. Field wiring connections to the 115-volt receptacle and lights are made at terminal block TB7, which is also located in the main control panel. Refer to Figure 74 and “Control Panel” on page 14. Two 7/8" knockouts are provided for wire entry.

Figure 74: RDT, RFS, RPS field control wiring connections

Main control panel

RFS/RCS Units

The RCS unit receives 115-volt and 240-volt control circuit power and a number of control signals from the RFS unit. Two 7/8" knockouts are provided in the right side of the RCS control box.

Interconnecting wiring enters the

RFS

unit through 7/8" knockouts in the bottom of the main control panel. The interconnecting wiring is connected to TB4 in the

RFS

unit and TB5 in the RCS unit. Refer to Figure 75. A 7/8" knockout is also available in the end of the unit base as shown in Figure 74.

Note – If a single conduit containing 24V and 115V wiring is run

Figure 75: RFS and RPS interconnecting control wiring

above the roof line between the RFS and RCS, install the 24V wiring as a NEC Class I wiring system.

Main

control

panel

Condenser

control

panel

TB4

PB4/DS4P

DS2

PB1/DS1

TB5

24V

115

4V field terminal

block (TB2)

Control wiring raceway cover (remove for access to harness from main contr box to unit-mounted control devices)

WARNING

Electrical shock hazard. Can cause severe injury or death. Connect only low voltage NEC Class II circuits to terminal block TB5. Reinstall and secure all protective deadfront panels when the wiring installation is complete.

64 McQuay IM 738-2

Preparing Unit for Operation

This b

Preparing Unit for Operation

WARNING

Moving machinery hazard. Can cause severe injury or death. Before servicing equipment, disconnect power and lock off. More than one disconnect may be required to de-energize unit.

Figure 76: RDT spring mount hold down fasteners

Hold-down fasteners

Spring Isolated Fans

Releasing Spring Mounts

The optional spring-mounted supply and return fans are locked down for shipment. Hold-down fasteners are located at each spring mount. Remove these fasteners before operating the fans. Figure 79 shows a typical spring mount. Note that the 3/8" hold-down bolt securing the fan base to the unit cross channel must be removed.

After removing the hold-down fasteners, rock the fan assembly by hand to check for freedom of movement.

Figure 77: Spring mounted hold-down fasteners, all units

racket is added,

and these 3/8" tie downs

are used for 15–30 ton units.

Figure 78: Fan spring mount adjustment

Leveling screw

Spring

mount

assembly

Cross

channel

* Grossly out-of-adjustment thrust restraints can affect this

dimension. Recheck after thrust restraints are adjusted.

Jam nut

Fan base

3/8" ± 1 /4" with fan running

Adjusting Spring Mounts

To change spring compression:

Loosen the .625-18 UNF hex nut.

Place some additional weight on the fan sled frame (use a lever to slightly compress the spring/or raise the sled) to allow the bolt to turn freely.

Place one or two drops of oil on the threads if needed. Use a wide, flat, blade socket drive bit with a recommended 1/2” drive handle. Ensure that as the slotted bolt is turned, the upper-rebound plate also turns. This action allows the bolt to compress/decompress the compression plate, while having the same affect on the spring. If the spring is compressed too much, lift the sled before turning. If the spring is not compressed enough, place weight on the sled corner to force it down before turning.

Re-adjust the position of the lower-rebound plate so that the sled has at lest 3/4” travel and no more than 1.25” travel.

Figure 79: Spring mount

This bracket is added,

and these 3/8" tie downs

re used for 15–30 ton units.

McQuay IM 738-2 65

Preparing Unit for Operation

WARNING

Moving machinery hazard. Can cause severe injury or death. Start the fans for the first time according to the “Check, Test, and Start Procedures” on page 112. If this is not done, equipment damage, severe personal injury, or death can occur.

Relief Damper Tie-Down

Figure 81: Thrust restraint adjustment

Jam nut A

Nut B

Spring clip

Washer

Nut C

Fan bulkhead

Economizer sections with a 30" or 40" return fan have a relief damper that is tied down for shipping. Remove the two brackets and two screws before operation to allow free movement of dampers. Access is from inside the economizer section.

Adjusting Scroll Dampers

Two sets of scroll dampers are provided in the housing of the twin 15" x 6" supply fan to allow control of air volume to each fan wheel. At the factory, these dampers are fully closed, unrestricting airflow. If fan paralleling occurs, correct it by loosening the adjustment screw on top of the fan housing (see Figure 80) and slightly lowering the rod until air distribution between the fans is even.

Figure 80: Scroll damper adjustment

Adjustment assembly

Scroll damper

Jam nut A

Thrust restraint angle

Fan housing frame

Detail A

See Detail A

Thrust restraint adjustment (with fan off)

1. Loosen jam nuts A.

2. Turn nut C until spring cup and washer contact thrust restraint angle.

3. Turn nut B until spring is compressed by two turns of nut B.

Adjusting Supply Fan Thrust Restraints

4. Tighten jam nuts A.

Thrust restraints are provided when housed double-width fans are mounted on springs. After the spring mounts are adjusted for level operation when the fan is running, check the thrust restraints. With the fan off, set the adjustment nuts so the spring is slightly compressed against the angle bolted to the fan housing frame. Refer to Figure 81. When the fan is turned on, the fan moves back to a level position and the thrust restraint spring compresses.

66 McQuay IM 738-2

Sequences of Operation

The following sequences of operation are for a typical “C” vintage applied rooftop unit equipped with MicroTech II, an economizer, 4-compressor/4-stage cooling, 3 to 1 turn down burner, variable frequency drives (VFD), a return air fan and an external time clock. These sequences describe the ladder wiring diagram logic in detail; refer to “Wiring Diagrams” on page 71 as you read them. Note that your unit’s sequences of operation may vary from those described here. Refer to the wiring diagrams supplied with the unit for exact information.

For detailed description of operation information relating to the MicroTech II controller's software, refer to the appropriate operation manual (see Table 1 on page 3). These manuals describe the various setpoints, parameters, operating states, and control algorithms that affect rooftop unit operation.

Power-up

When primary power is connected to the unit, 115VAC power is fed through control circuit transformer T1 and control circuit fuse F1C (line 168) to compressor crankcase heaters HTR-1, HTR-2, HTR-3 and HTR-4 (lines 815, 848, 820, and 853).

When system switch S1 (line 203) is closed, low voltage transformers T2 (line 203), T3 (line 301)and T9 (line 802) energize, and 115VAC power is supplied to the following:

• Smoke detectors (lines 265 and 267)

• Economizer actuator ACT3 (line 313)

• M30A to energize the supply fan VFD (line 426)

• M40A to energize the return fan VFD (line 430)

• Heating control panel (line 603)

• Compressor circuit switches CS1 and CS2 (lines 805 and

838)

Transformer T2 supplies 24VAC power to terminals 24V and COM on the main control board MCB (lines 207 and 208). Transformer T2 supplies 24VAC power to the following:

• Switch S7 On-Auto-Off (line 217)

• Enthalpy sensor OAE (line 250)

• External time clock contacts (line 215)

• External exhaust fan status contacts (line 257, VAV only)

• Airflow interlock switch PC7 (line 228)

• Dirty filter switches PC5 and PC6 (lines 242 and 247)

• Duct high limit switch DHL (line 260, VAV only)

• Gas furnace alarm relay R24 (line 225)

• Freezestat switch FS1 (line 231, hot water or steam heat

only)

• Smoke detectors SD1 and SD2 (line 237)

When the field supplied Cool Enable switch is in the OFF position, field wiring terminal TB2 105 de-energizes (line

220). Binary input MCB-BI3 de-energizes and the cooling is disabled. When the field supplied Heat Enable switch is in the OFF position, field wiring terminal TB2 106 de-energizes (line

223). Binary input MCB-BI4 de-energizes and the heating is disabled.

Note – Unit ships with factory installed jumpers between TB2 101

and 105 and between 101 and 106.

Fan Operation

When the main control board (MCB) commands the supply and return fans to start, the unit enters the Startup operating state. As a result, a 3-minute timer is set, output MCB-BO3 (line 307) energizes, and relay R26 energizes (line 306).

After the 3-minute timer expires, the unit enters the Recirc operating state. As a result, output MCB-BO1 energizes relay R67 (line 401). This gives a start signal to supply fan drive AFD10 (line 445). Four seconds after MCB-BO1 is energized, output MCB-BO2 energizes relay R68 (line 404). This gives a start signal to return fan drive AFD20 (line 445).

Within 120 seconds after the fans start, the controller expects airflow switch PC7 (line 228) to close and thus energize binary input MCB-BI6. (If MCB-BI6 does not energize, the controller assumes the fans did not start. It then shuts down the unit and generates an alarm.)

During the Recirc operating state, the outside air damper is held closed. The controller does this by energizing output MCB-BO5 (line 318). On VAV units, output MCB-BO12, the VAV box output, is also de-energized (line 309) during the Recirc state.

McQuay IM 738-2 67

Sequences of Operation

The supply fan adjustable frequency drive (AFD10) is modulated to maintain the duct static pressure setpoint. When energized, output MCB-BO14 (line 407) drives AFD10 toward increased capacity; MCB-BO13 (line 405) drives it toward decreased capacity. On VAV units or CAV units equipped with return fan capacity control, the adjustable frequency drive (AFD20) is modulated to maintain an acceptable building static pressure (using either VaneTrol logic or direct measurement of building pressure; see the appropriate OM for more information). When energized, output MCB-BO16 (line

409) drives AFD20 toward increased capacity; MCB-BO15 (line 411) drives them toward decreased capacity.

Note – If the inverter bypass switch S4 (lines426 and 430) is in

the bypass position, MMP30 and MMP40 (line 132 and

144) protect the fans from excessive current draw. If either the supply or return fan is drawing excessive current, one of the MMPs triggers an auxiliary contacts (line 426) and open the circuit, causing both fans to stop.

Economizer Operation

When the outdoor air is suitable for free cooling, the switch in enthalpy sensor OAE is in position “3” (line 252) energizing binary input MCB-BI11. When MCB-BI11 energizes, the economizer is enabled. (Note: If selected from the keypad, the enthalpy decision can be made based on outdoor temperature. In that condition, if the outdoor air temperature is less than or equal to the changeover set point, the economizer is enabled.) If cooling is required, the economizer dampers (ACT3) are modulated to maintain the discharge air temperature setpoint. When energized, output MCB-BO6 drives the outdoor air dampers toward the open position; MCB-BO5 drives them toward the closed (line 318). If the outdoor air dampers are wide open and more cooling is required, the dampers hold their positions and mechanical cooling is activated (see below).

When the outdoor air is not suitable for free cooling, the switch in enthalpy sensor OAE is in position “1,” de-energizing binary input MCB-BI11. (Alternatively, the outdoor air temperature is above the changeover setpoint plus the economizer changeover differential). When the economizer is disabled, the dampers are held at their minimum position.

Mechanical Cooling Operation

4-Compressor/4-Stage Unit

Refer to “VAV control inputs” on page 80 and “RPS 135 condensing unit control (with reciprocating compressors)” on

page 94 as you read this sequence of operation. In this configuration there are four equally sized compressors and two cooling circuits. In the following description, compressor #1 is lead. However, if Auto Lead/Lag Staging is selected on the keypad, the lead compressor is the one in the lead circuit with the least number of run hours.

When the unit disconnect is closed, 115VAC power is supplied directly from control transformer T1 to the compressor crankcase heaters, HTR-1, 2, 3, and 4 (lines 815, 848, 820,

853) and motor protectors MP1, 2, 3, and 4 (lines 816, 849, 821, 854). This same 115VAC source also goes through:

• System switch, S1 (line 203)

• The optional phase voltage monitors, PVM1 and 2

(lines 203, 802)

• The optional ground fault relays, GFR1 and 2

(lines 203, 802)

• Compressor control switches, CS1 and 2 (lines 823, 856)

• Transformer T9 is also powered (line 802)

Compressor control switches, CS1 and 2 provide 24VAC from transformer T9 to compressor control boards CCB1 and CCB2 (lines 805, 838) as well as the following cooling circuit binary inputs:

• Frost protect FP1 to CCB1-BI8 (line 811)—Optional when

no hot gas bypass is ordered on the unit

• Frost protect FP2 to CCB2-BI8 (line 844)—Optional when

no hot gas bypass is ordered on the unit

• HP relay R1 to CCB1-BI7 (lines 807)

• HP relay R2 to CCB2-BI7 (lines 840)

• Compressor contactor status M1 to CCB1-BI9 (line 808)

• Compressor contactor status M2 to CCB2-BI9 (line 841)

• Compressor contactor status M3 to CCB1-BI10 (line 809)

• Compressor contactor status M4 to CCB2-BI10 (line 842)

• Circuit pump down switch PS1 to CCB1-BI11(line 812)

• Circuit pump down switch PS2 to CCB2-BI11(line 845)

• Cool enable from MCB-B07 to CCB1-BI12 and CCB2-BI12

(lines 813, 846)

When manual pumpdown switches PS1 and PS2 are closed, all four compressors are fully enabled and ready to start if commanded to by the MicroTech II control system.

68 McQuay IM 738-2

Sequences of Operation

Cross Circuit Loading

If cooling is enabled (MCB-BI3 is energized—line 220) and mechanical cooling is required, the MCB energizes cool enable output MCB-BO7 (line 813) to binary inputs CCB1-BI12 (line 813) and CCB2-BI12 (line 846). The MCB also sends a digital communications signal to CCB1 and 2 to enable cooling. CCB1-BO4 output energizes and opens liquid line solenoid valve SV1 (line 831), allowing refrigerant to flow into the evaporator coil. As the refrigerant evaporates, the suction pressure increases until low pressure switch LP1 closes (line 815) as a binary input to CCB1-BI6. When CCB1 senses that LP1 has closed, CCB1-BO1 and BO5 energize contactors M1 and M11 (lines 817 and 832) to start compressor #1 and condenser fan #11. (The above description applies to units without the low ambient start option. For a description of low ambient start, see “Unit Options” on page 97 of this manual). Additional condenser fan stages are added as the outdoor air temperature rises above setpoints input through the keypad. CCB1-BO6 controls contactor M12 (line 833), which cycles condenser fan #12. CCB1-BO7 controls contactor M13 (line

834), which cycles condenser fan #13. This is stage 1.

If more cooling is required, CCB2-BO4 energizes and opens liquid line solenoid valve SV2 (line 864), allowing refrigerant to flow into the evaporator coil. As the refrigerant evaporates, the suction pressure increases until low pressure switch LP2 closes (line 848) as a binary input to CCB2-BI6. When CCB2 senses that LP2 has closed, CCB2-BO1 and BO5 energize contactors M2 and M21 (lines 850 and 865) to start compressor #2 and condenser fan #21. Additional condenser fan stages are added as the outdoor air temperature rises above setpoints input through the keypad. CCB2-BO6 controls contactor M22 (line 866), which cycles condenser fan #22. CCB2-BO7 controls contactor M23 (line 867), which cycles condenser fan #23. This is stage 2.

If more cooling is required, CCB1-BO2 energizes contactor M3 (line 822) to start compressor #3. This is stage 3.

If more cooling is required, CCB2-BO2 energizes contactor M4 (line 855) to start compressor #4. This is stage 4.

When the cooling demand is satisfied, MCB works through CCB1 and 2 to stage down the compressors. The compressor with the most hours on the lag circuit stages off first, and so on. When both circuits are running with only one compressor each (stage 2), less cooling is required and if circuit #2 is lag,

CCB2-BO4 de-energizes to close liquid line solenoid valve SV2 (line 864). As a result, compressor #2 pumps down refrigeration circuit #2 until the suction pressure drops low enough to open low pressure control LP2 (line 848). When LP2 opens, CCB2-BO1, BO5, (BO6 and BO7) de-energize to shut down compressor #2 and its associated condenser fan(s).

When mechanical cooling is no longer necessary, CCB1-BO4 de-energizes to close liquid line solenoid valve SV1 (line 831). As a result, compressor #1 pumps down refrigeration circuit #1 until the suction pressure drops low enough to open low pressure control LP1 (line 815). When LP1 opens, CCB1-BO1, BO5, (BO6 and BO7) de-energize to shut down compressor #1 and its associated condenser fan(s).

Lead Circuit Loading

The loading and unloading process is similar except that both compressors in the lead cooling circuit energize before energizing any compressors in lag circuit.

Compressor Protective Devices (see page 132)

If a compressor motor protector trips, it immediately disables its associated compressor contactor M1, 2, 3 or 4 (lines 817, 850, 822 and 855).

If high pressure switch HP3 trips (line 823), compressors #1 and #3 are disabled and relay R1 (836) signals CCB1-BI7 of the event (line 807). CCB1 then de-energizes CCB1-BO1 and BO2 (lines 817, 822) to keep compressors #1 and #3 locked out. If high pressure switch HP4 trips (line 856), compressors #2 and #4 are disabled and relay R2 (line 869) signals CCB2-BI7 of the event (line 840). CCB2 then de-energizes CCB2-BO1 and BO2 (lines 850 and 855) to keep compressors #2 and #4 locked out.

Note – The following frost control protection option is not

included in the wiring diagram (Figure 99 on page 93).

If frost protect switch FP1 trips (line 811), CCB1-BO4 de-energizes (lines 831) to close SV1 and pump down circuit #1. If frost protect switch FP2 trips (line 844), CCB2-BO4 de-energizes (lines 864) to close SV2 and pump down circuit #2. For both of these alarms, the circuit remains off for at least one cooling stage timer interval. If cooling is still needed, the cooling tries to restart. The cooling resets up to three times in a 24-hour period (between 2:00 a.m. and 2:00 a.m.). After the third trip, the alarm remains until manually cleared at the keypad or over the network.

McQuay IM 738-2 69

Sequences of Operation

Heating

Gas Furnace, Modulating Burner (3 to 1 turn down)

Refer to “Standard Mod, furnace control (1000 MBh)” on page 90 as you read this sequence of operation. Note that the gas furnace wiring diagrams supplied with the units include a detailed sequence of operation. Refer to the wiring diagram supplied with the unit for exact wiring and sequence of operation information.

When system switch S1 is closed, 115 V (ac) power is supplied to the furnace control circuit. If burner switch S3 and safeties HL22, HL23 are closed (line 603), terminal 5 (line 609) on the flame safeguard control (FSG) energizes as does the modulating gas valve VM1. If heating is enabled (MCB-BI4 is energized—line 223) and heating is required, the MCB-BO11 energizes relay R20 (line 413). The normally open R20 contacts (line 603) close, and if manual burner switch S3 and safeties HL22, HL23, FLC (high limit switch) (line 603), LP5, and HP5 are closed (optional, not shown on page 90), terminal 6 (line 618) on the flame safeguard control (FSG) energizes. FSG energizes terminal 4 to start the blower motor (BM) (line

609) through contactor M29 on large burners. If the blower is operational, air switch AS (line 621) closes and makes electrical continuity from FSG terminal 6 to 7. After a 90second prepurge period, FSG terminals 8 (line 613) and 10 (line 621) energize. As a result, ignition transformer IT and pilot gas valve GV1 energize. The pilot flame ignites and is detected by FSG through flame rod FD (line 612). Upon detection of pilot flame after the 10-second trial for ignition period, the FSG de-energizes terminal 10 and energizes terminal 9 to energize main gas valves GV2 and GV3 (lines 617, 619) and low fire start relay R23 (line 624). The R23 contacts (lines 632 and 633) allow the MCB to modulate gas valve actuator VM1 as required to satisfy the heating demand.

Whenever the burner is operating, its firing rate is determined by the position of gas valve actuator VM1. This actuator modulates the butterfly gas valve and combustion air damper,

thus varying the furnace firing rate between 33% and 100% of full capacity. When the MCB-BO10 energizes (line 634), VM1 modulates toward open and the firing rate increases. When MCB-BO9 energizes (line 633), VM1 modulates toward closed and the firing rate decreases. When both MCB-BO10 and MCB-BO9 are open, VM1 holds its position and the firing rate remains constant.

When heating is no longer necessary, MCB-BO11 opens, de-energizing relay R20 and opening its contacts (line 603). As a result, the flame safeguard control de-energizes, all gas valves close, the combustion air blower motor stops, and gas valve actuator VM1 closes. If the furnace is warm enough to close it, the FLC fan controls switch (line 602) overrides supply fan start/stop output MCB-BO1 through R25 (line 402) and keeps the supply fan running until the furnace cools down (this might happen during night setback operation).

If the furnace overheats, the FLC high limit control (line 603) cycles the burner, preventing the furnace temperature from exceeding the limit control’s setpoint. When the furnace cycles off, low fire start relay R23 de-energizes. The normally closed R23 contacts (line 633) cause VM1 to drive to its minimum position, overriding MicroTech II control of VM1 via MCB-BO10 and MCB-BO9. Because relay R23 de-energizes whenever GV2 de-energizes, the burner always starts at low fire.

Safety Lockout

If the pilot flame does not ignite or the flame safeguard fails to detect its flame within 10 seconds, the flame safeguard control enters the “safety lockout” state. FSG terminals 4, 8, 9, and 10 de-energize and the burner shuts down. FSG terminal 3 energizes relay R24 (line 610). The R24 contacts (line 225) signal the controller that the problem exists by energizing the input to MCB-BI5. If a safety lockout occurs, manually reset the flame safeguard control.

70 McQuay IM 738-2

Wiring Diagrams

Legend

General Notes

1. Field wiring

2. Factory wiring

3. Shielded wire/cable

4. Main control box terminals

5. Auxilliary box

6. Field terminals

7. Plug connector

8. Wire/harness number

9. Wire nut/ID

ID Description Standard location

ACT3, 4 Actuator motor, economizer Economizer section ACT5 Actuator motor, discharge

ACT6 Actuator motor, return air

ACT7 Actuator motor, heat face/

ACT8 Actuator motor, cool face/

ACT10, 11Actuator motor, exhaust

ACT12 Actuator motor, enthalpy

AFD10 Adjustable frequency drive,

AFD11 Adjustable frequency drive,

AFD20 Adjustable frequency drive,

AFD60 Adjust. freq. drive, energy

AS Airflow switch, burner blower Gas heat box BM Burner blower motor Heat section, gas C1–8 Power factor capacitors,

C10 Power factor capacitors,

C11 Capacitors, Speedtrol, circuit #1Condenser bulkhead

200/ H200

WN7

isolation damper

bypass

Bypass

dampers

wheel bypass damper

supply fan

evap cond. fans

return/exhaust fan

recovery wheel(s)

compressors

supply fan

terminals

Discharge section

Return section

Coil section, heat

Coil section, cool

Return section

Energy recovery section

AFD/supply fan section

Main/RCE control box

AFD/ret. ex. fan section

Energy recovery section

Condenser section

Supply Fan section

ID Description Standard location

C20 Power factor capacitors,

return fan

C21 Capacitors, Speedtrol, circuit #2Condenser bulkhead

CB10 Circuit breaker, supply fan Main control box CB11 Circuit breaker, evaporative

condenser fan(s)

CB20 Circuit breaker, return/

exhaust fan

CB60 Circuit breaker, energy

recovery wheel

CCB1, 2 Compressor control boards,

refrig. circuits

CPC Circuit board, main, micro

controller

CPR Circuit board, expansion,

micro controller

CS1, 2 Control switches, refrig.

circuits

DAT Discharge air temperature

sensor DFLH Design flow lefthand sensor Return section DFRH Design flow righthand sensor Return section DHL Duct hi-limit Main control box DS1 Disconnect, total unit or cond/

heat DS2 Disconnect, SAF/RAF/

controls DS3 Disconnect, electric heat Electric heat box DS4 Disconnect, condenser (RCS

Only) EAT Exhaust air temperature

sensor EFT Entering fan air temperature

sensor EHB1 Staged electric heat board Main control box ERB1 Energy recovery board Main control box ERM1 Energy recovery wheel motor #1Energy recovery section

ERM2 Energy recovery wheel motor #2Energy recovery section

F1A, B Fuse, control circuit

transformer (T1), primary F1C Fuse, control circuit

transformer (T1), secondary F2 Fuse, control circuit

transformer (T2), primary F3 Fuse, burner blower motor Main control box FB11, 12 Fuseblock, Speedtrol Main/cond. control box FB31–40 Fuseblock, electric heat (top

bank) FB41–50 Fuseblock, electric heat (bot.

bank) FB65 Fuseblock, evap. cond. sump

heater FD Flame detector Heat section, gas FLC Fan limit control Heat section, gas FP1, 2 Frost protection, refrig. circuits Coil section, cool FS1, 2 Freezestat control Coil section, heat/cool FSG Flame safeguard Gas heat box GCB1 Generic condenser board,

refrig. circ. GFR1, 2 Ground fault relay Main control box GFS1, 2 Ground fault sensor Main control box GFR4 Ground fault relay, condenser Condenser control box GFS4 Ground fault sensor,

condenser GRD Ground All control boxes

Return section

Main/cond. control box

Main control box

Main/cond. control box

Discharge section

Main control box

RCS control box

Energy recovery section

Supply fan section

Main control box

Electric heat box

Main/cond. control box

Main control box

Condenser control box

McQuay IM 738-2 71

Wiring Diagrams

ID Description Standard location

GV1 Gas valve, pilot Heat section, gas GV2 Gas valve, main/safety Heat section, gas GV3 Gas valve, redundant/safety Heat section, gas GV4–8 Gas valve, main, hi turn down Heat section, gas HL1–10 Hi-limits, pwr, elec heaters

(top bank)

HL11–20 Hi-limits, pwr, elec heaters

(bot. bank) HL22 Hi-limits, gas heat (pre-filters) Supply fan section HL23 Hi-limits, gas heat (final filters) Final filter section HL31–40 Hi-limits, ctl. elec heaters (top

bank) HL41–50 Hi-limits, ctl. elec heaters (bot.

bank) HP1–4 Hi-pressure controls, refrig On compressors HP5 Hi-pressure controls, gas Heat section, gas HS1 Heat switch, electric heat

shutdown HS3 Heat switch, electric heat

deadfront interlock HTR1–6 Crankcase heaters On compressors HTR65 Heater, sump Evap. condenser section HTR66 Heater, vestibule Evap. condenser vestibule HUM1 Humidstat sensor Energy recovery section IT Ignition transformer Gas heat box LAT Leaving air temperature

sensor LP1, 2 Low-pressure controls,

refrigeration LP5 Low-pressure control, gas Heat section, gas LR10 Line Reactor, supply fan Inverter bypass box LR20 Line reactor, return/exhaust

fan LS1, 2 Limit switch, low fire, high fire Gas heat box LT10–23 Light, cabinet sections Supply fan section M1–8 Contactor, compressor Main/cond. control box M10 Contactor, supply fan Main control box M11–18 Contactor, condenser fans,

circuit #1 M20 Contactor, return fan Main control box M21–28 Contactor, Condenser fans,

circuit #2 M29 Contactor, burner motor Gas heat box M30 Contactor, reversing, invertor

bypass, supply fan M31–39 Contactor, electric heat (top

bank) M40 Contactor, reversing, Invertor

Bypass, Return Fan M41–50 Contactor, electric heat (bot.

bank) M60 Contactor, energy recovery

wheel M64 Contactor, sump pump Main/cond. control box M65 Contactor, sump heater Main/cond. control box MCB Microprocessor circuit board Main control box MJ Mechanical Jumper All control boxes MMP1–8 Manual motor protector,

compressors MMP10 Manual motor protector,

supply fan MMP11–18Manual motor protector, cond.

fans, ckt#1 MMP20 Manual motor prote ctor, return

fan MMP21–28Manual motor protector, cond.

fans, ckt#2 MMP30 Manual motor protector, invrtr.

bypass, sup. fan MMP40 Manual motor protector, invrtr.

bypass, ret. fan

Heat section, electric

Main control box

Electric heat box

Energy recovery section

On compressors

Inv. bypass/main cont. box

Main/cond. control box

Inverter bypass box

Electric heat box

Inverter bypass box

Electric heat box

Main control box

Main/cond. control box

Main control box

Main/cond. control box

Main control box

Main/cond. control box

Inverter bypass box

ID Description Standard location

MMP51, 52, 53

MMP60 Manual motor protector,

MMP64 Manual motor protector, sump

MP1–6 Motor protector, compr.#1-6 On compressors OAE Outside air enthalpy sensor Economizer section OAT Outside air temperature

OP1–4 Oil pressure controls,

PB1, 2 Power block, power

PB3 Power block, power

PB4 Power block, power

PB9, 10 Power block, supply fan Junction box, split unit PB11, 12 Power block, power

PB19, 20 Power block, return/exhaust

PC5 Pressure control, clogged filter Pre filter section PC6 Pressure control, clogged final

PC7 Pressure control, proof airflow Supply fan section PC8 Pressure control, minimum

PC12, 22 Pressure control, Fantrol Condenser section PM1 Phone modem Main control box PS1, 2 Pumpdown switches, refrig

PS3 Pumpdown switch, RFS only Main control box PVM1, 2 Phase voltage monitor Main control box PVM4 Phase voltage monitor,

R1, 2 Relay, hi pressure reset Main/cond. control box R3, 4 Relay, hi pressure delay Main/cond. control box R5–8 Relay, safety, cool fail Main/cond. control box R9, 10 Relay, compressor lockout Main/cond. control box R11, 12 Relay, Speedtrol fan cycling Main/cond. control box R20 Relay, Heat, gas/ steam/ hot

R21, 22 Relay, heat, gas (hi-turn

R23 Relay, heat, gas & electric Gas/electric heat box R24 Relay, heat alarm, gas Main control box R25 Relay, heat, gas, start supply

R26 Relay, isol/exh. dampers,

R28 Relay, isolation damper,

R29 Relay, remote fire alarm Main control box R30 Relay, cool valve with face

R45 Relay, UV lights Main control box R46, 47 Relay, supply fan inverter,

R48, 49 Relay, return fan inverter, incr/

R56 Relay, heater, water pipe Main/RCE control box R58,59 Relay, heat wheel inverter,

R60 Relay, energy recovery wheel,

R61 Relay, smoke detector,

R62, 63, 65Relay, use on specials Main control box

R64 Relay, sump pump Main/RCE control box

Manual motor protector, exhaust fan(s)

energy recovery wheel

pump

sensor

compr.#1-4

distribution

distribution, electric heat

distribution, condenser

distribution

fan

filter

airflow

circuits

condenser

water

down)

fan inverter

open/close

safety

bypass

incr/decr

decr

incr/decr

enable

discharge air

Prop exhaust box

Main control box

Main/RCE control box

Economizer section

Condenser section

Main control box

Electric heat box

Condenser control box

Main control box

Junction box, split unit

Final filter section

Coil section, cool

Main/cond. control box

Condenser control box

Gas heat/main cont. box

Gas heat box

Main control box

72 McQuay IM 738-2

Wiring Diagrams

ID Description Standard location

R66 Relay, smoke detector, return

R67 Relay, supply fan, enable Main control box R68 Relay, return fan, enable Main control box R69 Relay, Inv. bypass VAV box

R70–79 Relay, use on specials Main control box RAE Return air enthalpy sensor Return section RAT Return air temperature sensor Return section REC1 Receptacle, main box Main control box REC2 Receptacle, condenser box Condenser control box REC3 Receptacle, field power, 115V Discharge bulkhead REC10–23Receptacle, cabinet sections Cabinet sections

S1 Switch, system on/off Main control box S2 Switch, system on/off,

S3 Switch, furnace on/off Gas heat box S4 Switch, inverter bypass, on/ off Main control box S7 Switch, local on/auto/off to

S10–23 Switches, cabinet section

S40–45 Switches, door interlock, UV

SC11 Speed control, circuit #1 Condenser bulkhead SC21 Speed control, circuit #2 Condenser bulkhead SD1 Smoke detector, supply Discharge section SD2 Smoke detector, return Return section SPS1, 2 Static pressure sensors, duct/

SR1-3 Sequencing relays, electric

SV1, 2 Solenoid valves, liquid Condenser section SV5, 6 Solenoid valves, hot gas Condenser section SV61, 62 Solenoid valves, sump, fill Main/RCE control box SV63 Solenoid valves, sump, drain Main/RCE control box SWT Sump water temperature

T1 Transformer, main control

T2 Transformer, control input

T3 Transformer, control output

T4 Transformer, exh. damper

T5 Transformer, electric heat Electric heat box T6 Transformer, dew point

T9 Transformer, refrig. circuit 24V Main control box T11 Transformer, speedtrol (line/

TB1 Terminal block, internal Main control box TB2 Terminal block, field Main control box TB3 Terminal blocks, factory Main control box TB4 Terminal block, RFS, field Main control box TB5 Terminal block, RCS, field Condenser control box TB6 Terminal block, RCS, factory Condenser control box TB7 Terminal block, 115V

TB8 Terminal block, 115V conv.

TB11 Terminal block, heat Heat control box TB23 Terminal block, oil pressure

TB25, 26, 27, 28

TC12, 13, 14

TC56 Temperature control, water

air

interlock

condenser unit

controller

lights

building

heat

sensor

(line/115 V (ac)

(115/24 V (ac)

actuator (115/12 V (dc)

controller (115/24 V (ac)

240 V (ac)

convenience outlet, field

outlet, RCS, field

box, RPE/RCE only Terminal block, split unit

junction box Temperature controls, Fantrol Condenser section

pipe heater

Main control box

Condenser control box

Main control box

Cabinet sections

Main control box

Electric heat box

Evap. condenser section

Main control box

Condenser section

Main control box

Condenser control box

Evap. condenser vestibule

Junction box, split unit

Evap. condenser vestibule

ID Description Standard location

TC66 Temperature control, vestibule

exhaust fan

TD1, 2 Time delay, compressor

lockout TD3, 4 Time delay, hi-pressure Main/cond. control box TD5–8 Time delay, part winding,

compr #1 - 4 TD10 Time delay, hi turn down

burner TD11, 12 Time delay, low ambient Main/cond. control box TR1, 2 Transducer, pressure Main control box U1, 2 Unloaders, compressors On compressers UV Ultra-violet light(s) Coil/discharge section VM1 Valve motor #1, heating Gas heat box/ heat section VM5 Valve motor #5, cooling Coil section, cool VV1 Vent valve, gas heat Heat Section, Gas WL63 Water level, sump, fill Evap. condenser section WL64 Water level, sump, low water Evap. condenser section ZNT1 Zone temp. sensor, setback Field installed

Evap. condenser vestibule

Main/cond. control box

Main control box

Gas heat box

McQuay IM 738-2 73

Wiring Diagrams

Figure 82: VAV fan power (with SAF and RAF VFDs and manual bypass)

+NB

SUPPLY-FAN

HSAF-1

MTR

HSAF-2

HSAF-3

PB11

109A

M30B

MMP30

133B

T1A

L1A

135B

134B

T3A

T3B

T2A

T2B

T1B

L3B

L3A

L2B

L2A

L1B

+BB

L3B

L3A

L2B

L2A

L1B

L1A

+BB

111A

110A

427

+BB

426

134A 138A 138B

425

GND

H140

135A 139A 139B

GND10

M30I

440

+NB

AFD10

+BB

LR10

133A 137A 137B

(Schematic continues on the next page.)

H139

H137

H138

CB10

L3L3

L1L1

L2L2

T3A

T2A

T1A

DS2

CIRCUIT #1

ELECTRICAL

107

108

T1B

SUPPLIED

CUSTOMER

109

T2B

POWER

110

T3B

GLG1

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

PB11

139

138

137

109

L3-3

L2-3

L1-3

137

138

139

140

141

142

74 McQuay IM 738-2

Figure 83: VAV fan power (with SAF and RAF VFDs and manual bypass), continued

+NB

MTR

RETURN-FAN

HRAF-1

HRAF-2

HRAF-3

168C

Wiring Diagrams

T1_N

/2.66

/8.00

/6.00

/4.00

/3.00

/2.00

M40B

MMP40

T3A

T3B

T2A

T1A

T2B

T1B

L3B

L3A

L2B

L2A

L1B

L1A

+BB

(Schematic continues on the previous page.)

M40I

AFD20

+BB

CB20

LR20

440

145A 149A 149B

H149

430

GND

H152

147A 151A 151B

146A 150A 150B

GND20

F1A

H151

H150

L3L3

L1L1

L2L2

PVM1

203

164

163

162

164A

162A162

F1B

567

GRD

X1X2

168B

115T1/2.00

F1C

123

TB1A TB1A

432

+BB

+NB

426

151

149

143

144

145

146

147

148

PB11

149

150

109

L3-6

L2-6

L1-6

150

151

152

153

154

155

156

157

158

159

160

161

PB11

162

164

109

L3-1

L2-1

L1-1

163

164

165

166

167

168A

T1_115VAC

168

/8.00

/2.00

169

170

McQuay IM 738-2 75

Wiring Diagrams

106

1071081091101111121

1331341351361371381391401

)

Figure 84: Constant volume fan power (SAF and RAF)

L3B

L3A

L2B

L2A

L1B

L1A

PB11

SUPPLY-FAN

HSAF-1

MTR

HSAF-2

HSAF-3

109A

DS1

CIRCUIT #1

ELECTRICAL

SUPPLIED

CUSTOMER

110A

POWER

111A

T1L1

M10

137A

138A

T2A

T1A

T1B

GLG1

MMP10

PB11

L2A

L1B

L1A

137

138

L1-3

426

139A

T3A

T3B

T2B

L3B

L3A

L2B

139

109

L3-3

L2-3

(Schematic continues on next page.

426

76 McQuay IM 738-2

Figure 85: Constant volume fan power (SAF and RAF), continued

MTR

RETURN-FAN

HRAF-1

HRAF-2

HRAF-3

168C

T1_N

/2.00

/3.00

/4.00

Wiring Diagrams

/8.00

567

GRD

X1X2

T1L1

M20

431

F1A

T3A

T3B

T2A

T1A

T2B

MMP20

PB11

T1B

426

L3B

L3A

L2B

L2A

L1B

L1A

151

149

150

109

L3-6

L2-6

L1-6

PB11

(Schematic continues on the previous page.)

162A

162

168B

164A

F1B

F1C

123

TB1A TB1A

164

109

L3-1

L2-1

L1-1

168A

/8.00

/2.00

T1_115VAC

144

145

146

147

148

149

150

151

152

161

162

163

164

165

166

167

168

169

170

McQuay IM 738-2 77

Wiring Diagrams

Figure 86: RPS 75 condensing unit power (with SpeedTrol and scroll compressors)

+NB

COND-FAN12

PL52

M12

T1A

MMP12

L1A

PB11

HCF12-1

T1L1

T1B

L1B

7L1

L1-7

MTR

HCF12-2

T2A

T2B

L2B

L2A

7L2

L2-7

HCF12-3

T3A

T3B

L3B

L3A

7L3

L3-7

833

109

+NB

COND-FAN13

PL53

HCF13-1

T1L1

M13

MTR

HCF13-2

HCF13-3

834

+NB

COND-FAN14

PL55

HCF14-1

M14

MTR

HCF14-2

HCF14-3

HCF23-3

867

+NB

COND-FAN24

PL63

HCF24-1

M24

MTR

HCF24-2

HCF24-3

868

+NB

COND-FAN22

PL61

HCF22-1

HCF22-2

835

M22

T1L1

T2A

T1A

T1B

MTR

T2B

HCF22-3

T3A

T3B

866

+NB

COND-FAN23

PL62

HCF23-1

T1L1

M23

MTR

HCF23-2

MMP22

L3B

L3A

L2B

L2A

L1B

L1A

4L6

4L5

4L4

9L2

L2A

T2A

HCM3-2

MTR

109

L3-9

L2-9

9L4

9L6

9L3

L3A

L3B

L2B

819

9L5

L3A

L2A

L1A

L3B

L2B

L1B

852

(Schematic continues on next page.)

MMP4

T2B

T3B

T3A

822

HCM3-3

+NB

T1B

T1A

T1 L1

HCM4-1

COMPR.4

T2A

HCM4-2

MTR

T2B

T3B

T3A

855

HCM4-3

109

L3-5

L2-5

L1-5

PB11

5L1

5L3

5L2

L3A

L2A

L1A

L3B

L2B

L1B

814

MMP1

T2B

T2A

T1B

T1A

HCM1-1

+NB

COMPR.1

T3B

T3A

HCM1-2

HCM1-3

817

T1 L1

MTR

5L4

5L6

5L5

L3A

L2A

L1A

L3B

L2B

L1B

847

MMP2

T2B

T2A

T1B

T1A

HCM2-1

+NB

COMPR.2

T3B

T3A

HCM2-2

HCM2-3

850

T1 L1

MTR

L1-9

PB11

9L1

L1A

L1B

MMP3

T1B

T1A

HCM3-1

+NB

COMPR.3

78 McQuay IM 738-2

Figure 86: RPS 75 condensing unit power (with SpeedTrol and scroll compressors, continued

Wiring Diagrams

+NB

COND-FAN11

HCF11-1

+NB

HCF11-S1

M11

F11

4L13 757-1

MTR

HCF11-2

HCF11-3

1111111

C11

24V

SC11

HCF11-S3

759-1

H738-2

3-2 3-1

H739-2

T3L3

832

4L14

T1L1

+NB

COND-FAN21

HCF21-1

24V

+NB

H740-2

H741-2

HCF21-S1

M21

F12

4L13 762-1

MTR

HCF21-2

HCF21-3

1111111

C21

SC21

HCF21-S3

T1L1

T3L3

865

764-1

4L14

(Schematic continues on previous page.)

PB?

L1A

MMP5

T1A

HCM5-1

+NB

COMPR.5

L3-7

L2-7

L1-7

7L4

7L6

7L5

L3A

L2A

L3B

L2B

L1B

824

L3A

L2A

L1A

L3B

L2B

L1B

857

MMP6

T2B

T2A

T1B

T3B

T3A

827

HCM5-2

HCM5-3

MTR

+NB

COMPR.6

T1A

HCM6-1

T2B

T2A

T1B

T3B

T3A

HCM6-2

HCM6-3

860

T1 L1

MTR

McQuay IM 738-2 79

Wiring Diagrams

Figure 87: VAV control inputs

168C

115V

204B

TB1B

24V

1415GRD

1610

CLASS 2

TB1B

111213

DISPLAY

KEYPAD

208C

N2+/8.06

209C

WHT

TO CCB1

N2-/8.06

210C

BLK

210D

DRN

REF/8.07

PWR

SENSOR)

(RETURN AIR

H224-2

DRN-4

225C

224C

BLK

DRN

214B

SENSOR)

(OUTDOOR AIR

OAT

+NB

H227-2

H226-1

PL3

+PP

227C

226C

WHT

BLK

DRN-4

227D

DRN

TEMPERATURE)

(ENTERING FAN

EFT

+NB

H228-1

H229-2

PL5

+PP

229C

228C

WHT

BLK

DFRH_DS

+NB

DRN-4

230C

DRN

SIDE)

(DRIVE

H232-2

H230-3

DRN-4

H231-1

PL22

233C

232C

231C

RED

WHT

BLK

DRN

+PP

5V+

5VDC

PWR SUP

5V-

214A

+NB

SPACE

ZNT1

ZONE OR

OVERRIDE

120

TB2

WHT

BLK

SENSOR

EXTERNAL RESET

TEMPERATURE

DISCHARGE AIR

REQ'D FOR NIGHT SETBACK OR SPACE RESET

121

132

GRD

133

219C

218C

217C

DRN

WHT

BLK

DRN

GRD

+PP

+NB

H220-1

PL2

220C

WHT

SENSOR)

(DISCHARGE AIR

DAT

H221-2

221C

BLK

DRN-4

221D

DRN

RAT

+NB

H223-1

PL1

+PP

223C

WHT

115T1/1.68

TB1D

24VAC

COM

REF

N2-

N2+

204A

MCB

BCNT

COMM. CARD

BACNET-MSTP

REF

N2-

N2+

MICROPROCESSOR CONTROL BOARD

WHT

BLK

DRN

211A

210A

209A

168B

203

PVM1

203A

156

200

TB2

BACnet MSTP

128

129

GRD

wiring not shown.

connection shown.

LON and BACnet IP

201A 200A

S1/6.00

INPUT

ANALOG

RS232 PORT

INPUT

BINARY

OR UNOCCUPIED

SHOWN IN NIGHT

A (DB9-MALE) CONNECTION

IS LOCATED ON DEADFRONT

+NB

TIME_CLOCK

CONN.

SERIAL

RS-232

NJ=VDC

2=MA

1=RTD

215A 215C

TB2

MODE

NOTES TO FIELD:

AI1

3=NTC

v t

SW1

BI1

102

AUTO

CONFIGURATION.

MICROTECH II ALARM

INTERNAL TIME CLOCK,

1. REFER TO I.M. FOR

2. TO ENABLE SOFTWARE

AI2

3=NTC

1=RTD

NJ=VDC

2=MA

v t

SW1

BI2

217A

104

TB2

OFF

MANUAL_ENABLE

TB2

JUMPERED

ENABLE SWITCHES

MUST NOT BE

INSTALLING COOL/HEAT

TERMINALS 101 & 102

JUMPERS WHEN

THE FIELD TO REMOVE

AI3

NJ=VDC

3=NTC

2=MA

1=RTD

SW1

BI3

220

105

TB2

COOL_ENABLE

101

TB2

AI4

NJ=VDC

3=NTC

2=MA

1=RTD

SW1

BI4

223

106

TB2

HEAT_ENABLE

101

TB_101

NJ=VDC

3=NTC

2=MA

1=RTD

BI5

225A

111

TB2

DURING NORMAL OPERATION

CONTACT MUST BE OPEN

610

R24

GAS HEAT ALARM

AI5

SW1

AI6

NJ=VDC

3=NTC

2=MA

1=RTD

v t

SW1

BI6

228A

108

TB2

+PP

PL15

PC7

+NB

AIR FLOW

H228-4 H228-1

+PP

PL15

AI7

NJ=VDC

1=RTD

231A

2=MA

3=NTC

SW1

BI7

v t

(Schematic continues on next page.)

v t

112

TB2

3/Y1/R

FS1

+NB

H231-1 H231-3

101

TB_101

TB2

/1.68 /1.6

168A

T1_115VAC T1_

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

80 McQuay IM 738-2

Figure 88: VAV control inputs, continued

445

204B

SIG_SD/2.41

313

ACT3

+NB

(OP)CW(CL)

CCW

H239-3

DRN-9

H240-4

+PP

PL11

240C

214B

238C

H241-5

241C

H243-4

+PP

PL18

214B

+PP

DFLH_ODS

+NB

DRN-4

PL23

234C

H234-2

SIDE)

(OPP

DRIVE

H235-1

H236-3

214B

236C

235C

Wiring Diagrams

107

TB2

24VCOM/2.51

VM1

+NB

(OP)

(CL)

CCW

H244-2

H245-3

DRN-1

246C

245C

244C

131

TB2

PWRCOM

+NB

SHS1

SPS1

(DUCT STATIC

SPACE

SENSOR

HUMIDITY

OUT

(0-5V)

126

PRES SENSOR)

127

GRD

440

+NB

AFD10

500HOM

H262-8

H261-10

PL7

+PP

10813

DRN-13

440

+NB

AFD20

500HOM

DRN-3

H264-6

H265-8

PL8

+PP

683

TB2

266C

265C

264C

263C

262C

252C

253C

254C

257C

261C

WHT

BLK

RED

WHT

BLK

DRN

RED

WHT

BLK

DRN

WHT

RED

BLK

DRN

WHT

BLK

DRN

INPUT

OPEN ANALOG

AI8

3=NTC

1=RTD

NJ=VDC

2=MA

1 3

SW1

BI8

113

237A

TB2

(Schematic continues on previous page.)

PL20

+PP

PL20

H237-4

H235-5

235A

265267

SD1

+NB

H237-3

+PP

PL21

+PP

PL20

H237JMP

H235-6

+PP

PL21

H237-5

SD2

+NB

H237-3

+PP

PL21

3 4

NJ=VDC

AI9

3=NTC

1=RTD

2=MA

1 3

SW4

FILTER

FOR FIELD

INDICATION

243A

AI10

10C

3=NTC

1=RTD

NJ=VDC

2=MA

1 3

SW4

#10

BI9

AI11

11C

NJ=VDC

3=NTC

2=MA

1=RTD

SW4

#11

BI10

NJ=VDC

3=NTC

1=RTD

2=MA

AI12

12C

SW4

BI11

3=NTC

1=RTD

NJ=VDC

2=MA

1 3

15V DC

#12

BI12

252A

109

SIG_SD/2.38

TB2

242A

+PP

PL14

24VCOM/2.47

204B

+PP

PL13

204B

H252-2

H242-3

H243-1

R61

R66

PC5

+NB

PRE FILTER

H242-4

+PP

PL14

H250-4

TR1TR

HUM

OAE

+NB

JPR

H25O-+

H252-1

H25O-SR

+PP

PL13

RAE

+NB

OPEN ANALOG

AI13

13C

1=RTD

NJ=VDC

2=MA

1 3

SW4

#13

BI13

257A

103

TB2

EXS

+NB

EXTERNAL EXHAUST SWITCH

(SHOWN WITH FAN IN OFF POSITION)

INPUT

AI14

3=NTC

WHT

BLK

DRN

WHT

BLK

DRN

14C

SW4

3=NTC

1=RTD

NJ=VDC

2=MA

3=NTC

1=RTD

NJ=VDC

2=MA

1 3

#14

BI14

260A

DHL

AI15

1 3

SW4

AI16

15C

#15

16C

3=NTC

1=RTD

NJ=VDC

2=MA

3=NTC

1=RTD

NJ=VDC

2=MA

1 3

SW4

#16

BI15

BI16

168C

T1_N

/1.68

+PP

PL21

PL20

H265-2

H267-2

115

SD1

SD2

+NB

DUCT HI-LIMIT

SA SMOKE DETECTOR

RA SMOKE DETECTOR

H265-1

H267-1

+PP

PL21

PL20

203B

/8.01

/4.00

/3.00

T2_115VAC

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

McQuay IM 738-2 81

Wiring Diagrams

/1.68 /1.68

(Schematic continues on next page.)

Figure 89: CV control inputs

168C

115V

TB1D

PVM1

203A

(RETURN AIR

RAT

AI4

3=NTC

SW1

TB_101

SENSOR)

H224-2

224C

BLK

106

v t

DRN-4

225C

DRN

214B

SIDE)

+PP

DFLH_ODS

+NB

DRN-4

PL23

234C

DRN

H234-2

BLK

(OPP

DRIVE

H235-1

H236-3

214B

236C

235C

RED

WHT

SENSOR)

(OUTDOOR AIR

OAT

+NB

H226-2

H226-4

H225-1

+PP

PL3

226C

227D

227C

WHT

BLK

DRN

DFRH_DS

+NB

+PP

H230-3

PL22

RED

(DRIVE

H231-1

231C

WHT

SIDE)

H232-2

DRN-4

233C

232C

BLK

DRN

INPUT

OPEN ANALOG

NJ=VDC

1=RTD

AI5

3=NTC

2=MA

BI5

AI6

NJ=VDC

3=NTC

2=MA

1=RTD

v t

SW1

BI6

AI7

NJ=VDC

3=NTC

1=RTD

2=MA

v t

SW1

BI7

AI8

3=NTC

1=RTD

NJ=VDC

2=MA

SW1

BI8

1133113

TB2

235A

PL21

H235-6

237A

PL20

+PP

PL20

H237-4

H235-5

265267

SD1

+NB

H237-3

+PP

PL20

H237JMP

+PP

PL21

H237-5

SD2

+NB

H237-3

+PP

PL21

3 4

228A

TB2

+PP

PL15

231A

108

112

TB2

+PP

3/Y1/R

PC7

+NB

AIR FLOW

H228-4 H228-1

+PP

PL15

FS1

+NB

H231-1 H231-3

TB_101

TB2

101

5V+

5VDC

PWR

PWR SUP

204B

GRD

1610

TB1B

24V

CLASS 2

111213

TB1B

COM

24VAC

TO CCB1

N2+/8.06

N2-/8.06

REF/8.07

210D

210C

209C

DISPLAY

KEYPAD

WHT

BLK

DRN

208C211C

REF

N2-

N2+

204A

MCB

BCNT

COMM. CARD

BACNET-MSTP

REF

N2-

N2+

MICROPROCESSOR CONTROL BOARD

WHT

BLK

DRN

128

129

GRD

TB2

BACnet MSTP

wiring not shown.

connection shown.

LON and BACnet IP

5V-

A (DB9-MALE) CONNECTION

RS232 PORT

IS LOCATED ON DEADFRONT

CONN.

SERIAL

RS-232

+NB

214A

TB2

BLK

INPUT

ANALOG

NJ=VDC

1=RTD

INPUT

BINARY

215A 215C

TB2

MODE

OR UNOCCUPIED

SHOWN IN NIGHT

+NB

TIME_CLOCK

ZNT1

OVERRIDE

2=MA

NOTES TO FIELD:

ZONE

SENSOR

120

RED

AI1

3=NTC

SW1

BI1

102

MICROTECH II ALARM

1. REFER TO I.M. FOR

121

v t

AUTO

CONFIGURATION.

INTERNAL TIME CLOCK,

2. TO ENABLE SOFTWARE

SETPOINT

HEATING

COOLING &

132

GRD

217C

WHT

DRN

AI2

3=NTC

1=RTD

NJ=VDC

2=MA

SW1

BI2

217A

104

TB2

OFF

MANUAL_ENABLE

JUMPERED

MUST NOT BE

TERMINALS 101 & 102

JUMPERS WHEN

THE FIELD TO REMOVE

WALLSTAT

v t

TB2

ENABLE SWITCHES

INSTALLING COOL/HEAT

(DISCHARGE AIR

DAT

+NB

H220-1

PL2

+PP

220C

WHT

AI3

NJ=VDC

3=NTC

2=MA

1=RTD

SW1

BI3

220

105

TB2

COOL_ENABLE

101

SENSOR)

H221-2

221C

BLK

DRN-4

222C

DRN

TB2

+PP

+NB

H223-1

PL1

223C

WHT

NJ=VDC

2=MA

1=RTD

BI4

223

TB2

HEAT_ENABLE

101

333435

203B

168A

T1_115VAC T1_

020304

82 McQuay IM 738-2

0607080910

121314151617181920

212223242526272829

303132

Figure 90: CV control inputs, continued

(Schematic

continues

page

)

Wiring Diagrams

131

TB2

PWRCOM

252

+NB

SHS1

SPACE

SENSOR

HUMIDITY

OUT

(0-5V)

127

GRD

126

TB2

254C

253C

252C

WHT

BLK

DRN

WHT

BLK

DRN

DFRH_DS

+NB

107

TB2

24VCOM/2.51

ACT3

+NB

DRN-9

PL11

238C

DRN

CCW

H239-3

214B

RED

313

(OP)CW(CL)

H240-4

240C

WHT

H241-5

241C

BLK

SIDE)

+PP

DFLH_ODS

+NB

DRN-4

H234-2

PL23

234C

DRN

(OPP

DRIVE

H235-1

H236-3

236C

RED

+PP

214B

235C

WHT

BLK

SIDE)

(DRIVE

H232-2

H230-3

DRN-4

H231-1

+PP

PL22

233C

232C

231C

RED

WHT

BLK

DRN

343

VM1

+NB

(OP)

(CL)

CCW

H243-4

H244-2

H245-3

DRN-1

+PP

PL18

246C

245C

244C

214B

RED

DRN

WHT

BLK

INPUT

+PP

PL6

H247-4

+NB

+PP

PC6

PL6

BI10

H247-1

NJ=VDC

248A

H248-2

OPEN ANALOG

AI11

11C

3=NTC

2=MA

1=RTD

SW4

#11

NJ=VDC

AI12

12C

3=NTC

1=RTD

2=MA

3=NTC

1=RTD

2=MA

SW4

#12

BI11

252A

24VCOM/2.47

204B

+PP

+NB

FINAL FILTER

+PP

PL13

H252-2

H250-4

TR1TR

OAE

HUM

JPR

H25O-+

H252-1

H25O-SR

PL13

RAE

+NB

NJ=VDC

AI9

3=NTC

1=RTD

2=MA

SW4

FILTER

TB2

FOR FIELD

INDICATION

AI10

10C

3=NTC

1=RTD

NJ=VDC

2=MA

SW4

#10

BI9

243A

109

242A

+PP

PL14

H242-3

H243-1

PC5

+NB

PRE FILTER

H242-4

+PP

PL14

AI7

3=NTC

1=RTD

NJ=VDC

2=MA

231A

SW1

BI7

112

TB2

3/Y1/R

FS1

+NB

H231-1 H231-3

101

204A

TB_101

TB2

AI8

3=NTC

1=RTD

NJ=VDC

2=MA

SW1

235A

PL21

H235-6

BI8

113

237A

PL20

+PP

PL20

H237-4

H235-5

265267

SD1

+NB

H237-3

+PP

PL20

H237JMP

+PP

PL21

H237-5

SD2

+NB

H237-3

+PP

PL21

3 4

TB2

+PP

INPUT

253 253

OPEN ANALOG

AI13

13C

3=NTC

1=RTD

NJ=VDC

2=MA

15V DC

SW4

#13

BI12

INPUT

OPEN ANALOG

AI14

14C

3=NTC

1=RTD

NJ=VDC

2=MA

SW4

#14

BI13

INPUT

OPEN BINARY

INPUT

OPEN ANALOG

AI15

15C

3=NTC

1=RTD

NJ=VDC

2=MA

SW4

#15

BI14

BI15

INPUT

NJ=VDC

INPUT

OPEN ANALOG

AI16

16C

3=NTC

1=RTD

2=MA

SW4

#16

BI16

168C

T1_N

/1.68

OPEN BINARY

+PP

PL21

PL20

H265-2

H267-2

115

SD1

H265-1

SD2

+NB

RA SMOKE DETECTOR

H267-1

+PP

PL21

+NB

SA SMOKE DETECTOR

+PP

PL20

203B

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

/3.00

T2_115VAC

267

268

269

McQuay IM 738-2 83

/8.01

Wiring Diagrams

Figure 91: Control actuator outputs (CV, stream, or hot water, plus economizer)

364 362

168C

T1_NT2_115VAC

/1.68/2.68

2 COILS

EXCEED 15 VA

MUST HAVE 24VAC CLASS

MOUNTED RELAYS CAN NOT

THE TOTAL VA OF THE FIELD

NOTES TO FIELD:

1. ALL FIELD MOUNTED RELAYS

117115

TB2TB2

R26

102

(EXT_ALARM_SIGNAL)

24V

115V

CLASS 2

303A 303B

TB1C TB1C

305A

1819 20 21

jprs

24V SRC

4NO4

BO4

MCB

1-8

SRC

207

SOURCE 1-8

WIRED INTERNAL

TO MOTHERBOARD

(FAN_OPERATION)

116

TB2

307A

jprs

24V SRC

3NO3

BO3

207

MCB

/4.00 /4.00

T3_24V T3_COM

+NB

+PP

239

ACT3

PL11

H313-2

(ECON/ACT)

H313-1

PL11

+PP

PL11

6NO6

BO6

207

H315-8

3-CCW

+PP

H316-7

X-COM

2-CW

H315-6

+PP

PL11

315A 315B

(OPEN)

MCB

jprs

24V SRC

PL11

318A

5NO5

BO5

207

(CLOSE)

MCB

jprs

24V SRC

(Schematic continues on next page.)

203B

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

84 McQuay IM 738-2

Figure 92: Control actuator outputs (CV, stream, or hot water, plus economizer), continued

Wiring Diagrams

jprs

24V SRC

B09

(CLOSE)

+PP

PL18

H343-9

jprs

24V SRC

10NO10 9NO9

B10

207 207

(OPEN)

MCB M CB

339A 339C

(Schematic continues on previous page.)

+NB

243

VM1

+PP

PL18

+PP

PL18

H343-5H343-6

H344-8

3-CCW2-CW

HEAT

X-COM

H344-7

PL18

+PP

PL18

SIDE)

RELIEF

DAMPER

(OPP.DR

+NB

ACT11

BLK

WHT

H969

H968

5555555

6666666

H365-1

H366-3

+PP

PL17

363B

R26

306

362A 362B

TB1F

SIDE)

(DRIVE

RELIEF

DAMPER

+NB

ACT10

WHT

BLK

H965

H964

367A

TB1F

-+ DC

12V

115V

368A

TB1F

RECT

RECTIFIER

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

McQuay IM 738-2 85

Wiring Diagrams

Figure 93: VFD control (SAF and RAF)

/1.68/2.68 /3.11 /3.11

427 445

T1_NT2_115VAC

432 445

168C

631603

445

137

PL7

+PP

309

445

133

149

145

PL8

+PP

303B

102

R67

102

H1C

R46_47

H1DN

447

H1UP

R68

R48_49

H1DN

H1C

447

+PP

PL18

H1UP

C3C1

R20

+GB

A2A1

+BB

M30I

M30B

H427-9

H425-12

PL7

+PP

PL7

+PP

H425-2

H429-11

A2A1

R69

A2A1

+BB

M40I

H429-10

PL8

+PP

A2A1

+BB

M40B

H431-7

PL8

+PP

427B

604

R25

409A

407A

405A

1NO1

207

SUPPLY FAN

404A

jprs

BO2

MCB

24V SRC

2NO2

207

RETURN FAN

BO13

MCB

24V SRC

14NO14

13NO13

BO14

207

SAF DECR

MCB

SAF INCR

jprs

24V SRC

15NO15

BO16

BO15

207

RAF DECR

MCB

401A

jprs

24V SRC

BO1

MCB

411A

24V SRC

H413-7 H413-6

+PP

PL18

413A

jprs

24V SRC

16NO16

11NO11

BO11

207

RAF INCR

HEAT ENABLE

MCB

425A

INVERTER

1NC

AIR

SUPPLY

426B

PL8

+PP

401

R67

429A

427A

1NO

BYPASS

INVERTER

SIG_1/6.01

2NC

AIR

RETURN

404

R68

431A 431B

2ND

BYPASS

(Schematic continues on next page.)

H426-4H426-6H426-3

+BB

MMP40

H426-1

PL8

+BB

+PP

426A

PL7

+PP

MMP30

PL7

+PP

12(32)11(31) 12(32)11(31)

133 145

T3_24V T3_COM

45 42

TB2 TB2

SOURCE 9-16

WIRED INTERNAL

TO MOTHERBOARD

MCB

9-16

SRC

207

303A

203B

86 McQuay IM 738-2

Figure 94: VFD control (SAF and RAF), continued

149

264

1216

RAF

+NB

AFD20

ABB401

1113

+PP

PL8

H443-2

+PP

PL8

H443-5

Wiring Diagrams

443H

H2DNH2VH2UP

DECRINCR

443G

409

R66

R68

445C 445D

PL8

+PP

R48_49

404 241430

H443C

+PP

PL8

H443-12

+PP

PL7

H443-1

137

261

(Schematic continues on previous page.)

1216

SAF

+NB

AFD10

ABB401

1113

+PP

PL7

H443-4

H443A

H443-15

1413

+BB

M40I

443E

443D

H2DNH2VH2UP

DECRINCR

443C

405

351413

R46_47

R61M30I

401 239425

R67

445A 445B

PL7

+PP

H443-14

+BB

+PP

H443-7

PL7

443A

McQuay IM 738-2 87

Wiring Diagrams

Figure 95: Super Mod gas furnace control (1000 MBh)

402

H604-5

+PP

PL19

T1_N

/1.68

168C

+MB

R25

TB11

604B

+PP

PL19

H604-3

TB11

RED_G602-L1

604A

FLC

RED_G603-L3

413

RED_G602-L1

R20

TB11

RED_G602-L2

607A

602A

TB11

H603-4

+PP

PL19

H602-2

603A 603B 603C

+PP

PL19

PL16

+PP

H603-2

426B

SIG_1/4.28

21 42

HL22

225

627

TB11

R22

20202020202020

R24

+MB

WHITE

WHTBLK

GV1A

+PP

PL19

BLACK

H610-1

BLKBLK

19191919191919

GV1B

WHITE

WHTBLK

GV4A

GV4B

BLACK

SEE THE PIPING SCHEMATIC BELOW

REQUIRED FOR YOUR BURNER SIZE

FOR THE NUMBER OF MAIN GAS VALVES

21212121212121

C2C1

R23

TB11

RED_G609-L WHT_G609-R

RED_G613-L

LS1

RED_G617-L WHT_G617-R

NOCOM

R23

625

TB11

BLACK BLACK

TB11

610A 610B

613A 613B

611A

4K1

617A

2K2

621C

107

5K12K11K1

3K1

MICROCOMPUTER

FIER

FSG

AMPLI

FLAME

FSG-F

FSG-G

(FLAME ROD)

(FLAME SAFEGUARD)

(PLUG-IN TYPE

CONTROLLER)

621B

ASLS2

COM

621A

COM

FSG

6K1

(L1)

TB11

632615

632628

C2C1

R21

IGNITION TRANSFORMER

115V

6000V

2131

TD10

628A

612

R22

TB11

R21

10NO10

BO10

207

MCB

+MB

jprs

+MB

+PP

PL19

H632-9

24V SRC

9NO9

BO9

207

MCB

+PP

PL18

+PP

PL18

H633-9

H634-8

TB11

633A 633B

625

634A 634B

R23

628

R21

631A

632A 632B

413

R20

YEL_G632-R

YEL_G633-1

COM

VM1

VALVE

ACTUATOR

(FLOATING)

GAS & AIR

MODULATING

(OP)

BLK WHT

628

RED_G630-B WHT_G630-W

YEL_G634-2

OPEN

(CL)

CCW

(Schematic continues on next page.)

H603-1

+PP

PL16

S1/2.01

201A

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

(FSG) CONTROLLER.

COMBINATION VALVE WITH PRESSURE

LIGHTS ARE PART OF THE FLAMESAFEGUARD

IS THE SECOND VALVE OF A REDUNDANT

1.POWER, PILOT & MAIN VALVE INDICATION

2. GV-A IS THE FIRST VALVE AND GV-B

NOTE:

REGULATION AND MANUAL SHUTOFF

630

631

632

633

634

635

636

88 McQuay IM 738-2

Figure 96: Super Mod gas furnace control (1000 MBh), continued

(THRU 1/2 P.S.I.)

COCK

SHUTOFF

PIPING DIAGRAM

COCK

SHUTOFF

REG.

HIGH PRESS.

Wiring Diagrams

OVER 1/2 P.S.I.

WHEN 120 VOLT

(Schematic continues on previous page.)

SAFEGUARD (FSG). UPON A CALL FOR HEAT, THE CONTROL SYSTEM WILL CLOSE (BO#11) ON THE MAIN CTRL BRD (MCB), THUS ENERGIZING RELAY (R20).

WHEN THE ROOFTOP UNIT IS ENERGIZED 120 VOLT POWER IS SUPPLIED TO THE SYSTEM ON-OFF SWITCH (S1), TO BURNER ON-OFF SWITCH (S3) AND 24 VOLTS TO THE (BO#11)

POWER IS FURNISHED THROUGH THE SYSTEM ON-OFF SWITCH (S1), THROUGH THE BURNER ON-OFF SWITCH (S3), THROUGH RELAY (R20 CONTACTS, THROUGH THE HIGH LIMIT

CONTACTS ON THE MAIN CTRL BRD (MCB). BURNER ON-OFF SWITCH (S3) WILL POWER THE MODULATING GAS VALVE ACTUATOR (VM1) AND TERMINAL #5(L1) ON THE FLAME

SEQUENCE OF OPERATION

PREPURGE PERIOD WILL BEGIN.

BLOWER MOTOR (BM). WHENEVER POWER IS RESTORED TO THE FLAME SAFEGUARD, THE FLAME SAFEGUARD WILL GO THROUGH A 10 SECOND INITIATION PERIOD BEFORE THE

CONTROL (FLC) AND TERMINAL #6 ON THE FLAME SAFEQUARD (FSG) IS POWERED. THE FLAME SAFEGUARD THEN ENERGIZES ITS TERMINAL #4, WHICH POWERS THE BURNER COMBUSTION AIR

THE BURNER AIR CONTROL VALVE WILL BE AT THE MINIMUM POSITION DURING OFF CYCLES. UPON A CALL FOR HEAT OR ANY OTHER TIME THAT A PREPURGE CYCLE OCCURS

AIR SWITCH (AS). THIS INITIATES THE 60 SECOND PREPURGE CYCLE. CONCURRENTLY, (LS2) POWERS TIMER (TD10) WHICH WILL ENERGIZE RELAY (R21) AFTER 20 SECONDS.

POSITION FOR PREPURGE. WHEN THE AIR CONTROL VALVE REACHES THE FULL OPEN POSITION SWITCH (LS2) IS 'MADE', POWERING (FSG) TERMINAL #7 THROUGH THE BURNER

FOR A NEW CALL FOR HEAT, (VM1) THROUGH THE N/O CONTACTS OF (R20) AND THE N/C CONTACTS OF (R21), WILL RE-POSITION THE BURNER AIR VALVE TO ITS MAXIMUM OPEN

WHEN (R21) IS ENERGIZED (VM1) WILL START THE AIR CONTROL VALVE ON ITS WAY TOWARD THE MINIMUM AIR VALVE POSITION THROUGH THE N/O CONTACT OF (R21) AND THE

(VM1), THROUGH THE N/C CONTACTS OF (R20) AND (R23), POSITIONS THE BURNER AIR AND GAS CONTROL VALVES TO MINIMUM AFTER A RUN CYCLE. WHEN (R20) IS ENERGIZED

THE AIR CONTROL VALVE WILL BE RE-POSITIONED TO THE MAXIMUM POSITION FOR THE PREPURGE AND THEN RETURNED TO THE MINIMUM POSITION FOR LOW FIRE START.

IGNITION PERIOD TERMINAL #10 (IGNITION TRANSFORMER--IT) WILL BE DE-ENERGIZED AND TERMINAL #9 (RELAY R23 COIL AND MAIN GAS VALVES--GV4 & GV5) WILL BE ENERGIZED

AND THE CONTROL SYSTEM WILL BE ALLOWED TO CONTROL THE FIRING RATE. THE FLAME SAFEGUARD CONTAINS "LEDS"(LOWER LEFT CORNER) THAT WILL GLOW TO INDICATED OPERATION.

(LS1) WILL BE 'MADE'. IF (LS1) IS NOT 'MADE' THE COMBINATION GAS CONTROL START VALVES (GV1) WILL NOT OPEN AND THE BURNER WILL GO OUT ON SAFETY LOCKOUT.

N/C CONTACT OF (R23). AT THE COMPLETION OF THE 60 SECOND PREPURGE CYCLE THE VALVE WILL BE AT THE MINIMUM OPEN POSITION AND THE MINIMUM POSITION SWITCH

TERMINAL #10 (IGNTION TRANSFORMER--IT) WILL BE ENERGIZED. IF FLAME IS BEING DETECTED THROUGHT THE FLAME ROD (FD) AT THE COMPLETION OF THE 10 SECOND TRIAL FOR

AFTER COMPLETION OF THE 60 SECOND PREPURGE PERIOD THERE WILL BE A 10 SECOND TRIAL FOR IGINITION DURING WHICH TERMINAL #8 (COMBINATION GAS VALVE--GV1) AND

AFTER THE FLAME HAS LIT AND BEEN PROVEN, RELAY (R23) IS ENERGIZED ALLOWING (VM1), AS CONTROLLED BY (BO#9) & (BO#10) ON THE MAIN CTRL BRD (MCB), TO POSITION

AT ITS PRESENT POSITION. THE HEATING CAPACITY IS MONITORED BY THE MAIN CTRL BRD (MCB) THROUGH (AI#10) VIA A POSITION FEEDBACK POTENTIOMETER ON THE ACTUATOR.

THE ACTUATOR WILL RE-POSITION TOWARD A LOWER FIRING RATE. IF NEITHER (BO#9) OR (BO#10) ON THE MAIN CONTROL BOARD (MCB) ARE CLOSED, THE ACTUATOR WILL REMAIN

WILL RE-POSITION TOWARD A HIGHER FIRING RATE UNTIL (BO#10) OPENS OR THE ACTUATOR REACHES ITS MAXIMUM POSITION. WHEN THE MAIN CONTROL SYSTEM CLOSES (BO#9),

THE BURNER AIR AND GAS VALVES FOR THE REQUIRED FIRING RATE. WHEN THE MAIN CONTROL SYSTEM CLOSES (BO#10) ON THE MAIN CTRL BRD (MCB), THE GAS VALVE ACTUATOR

INPUT #5 ON THE MICROTECH II MAIN CONTROL BOARD (MCB).

TERMINAL #3 WILL ENERGIZE THE HEAT ALARM RELAY (R24), WHICH WOULD THEN ENERGIZE THE REMOTE 'HEAT FAIL' INDICATOR LIGHT AND SEND A FAIL SIGNAL TO BINARY

THUS DE-ENERGIZING THE BURNER AND TERMINAL #3 WILL BECOME ENERGIZED. THE FLAME SAFEGUARD WOULD THEN BE ON SAFETY LOCKOUT AND WOULD REQUIRE MANUAL RESETTING.

IN THE EVENT THE FLAME FAILS TO IGNITE OR THE FLAME SAFEGUARD FAILS TO DETECT ITS FLAME WITHIN 10 SECONDS, TERMINALS #4, 8, 9, AND 10 WILL BE DE-ENERGIZED,

--FIRST

VALVE AND

GV1A

MANUAL VALVE.

(TYPICAL)

VALVE AND

PRESS. REG.

TEST

COCK

CONN.

GV4B GV4A

GV5B GV5A

MODULATING

ACTUATOR

AIR

BURNER

BLOWER

SWITCH

--MAIN

COMBINATION GAS CONTROLS

GV1B

THE EARLIER DESCRIBED PREPURGE CYCLE WITH THE WIDE OPEN AIR VALVE WILL BE REPEATED.

IF AN ATTEMPT IS MADE TO RESTART THE BURNER BY RESETTING THE FLAME SAFEGUARD, OR IF AN AUTOMATIC RESTART IS INITIATED AFTER FLAME FAILURE,

IF THE UNIT OVERHEATS, THE HIGH LIMIT CONTROL (FLC) WILL CYCLE THE BURNER, LIMITING FURNACE TEMPERATURE TO THE LIMIT CONTROL SET POINT.

McQuay IM 738-2 89

Wiring Diagrams

Figure 97: Standard Mod, furnace control (1000 MBh)

402

H604-5

TB11

+PP

PL19

T1_N

/1.68

168C

+MB

87 8

R25

604B

+PP

PL19

H604-3

TB11

RED_G602-L2

FLC

RED_G602-L1

R20

TB11

RED_G602-L1

RED_G603-L3

413

604A

225

TB11

R24

+MB

+PP

PL19

BLK

H610-1

BLKBLK

GV1

BLK

BLACK BLACK

TB11

RED_G609-L WHT_G609-R

WHT_G617-R

GV2

BLACK WHITE

RED_G617-L

TB11

632

C2C1

202020202020

WHT

GV3

BLK

BLACK WHITE

21212121212121

619

R23

624

IGNITION TRANSFORMER

115V

6000V

BLACK BLACK

10NO10

BO10

207

jprs

MCB

+MB

24V SRC

jprs

9NO9

BO9

24V SRC

207

MCB

+MB

633B

634B

632B

+PP

PL19

H632-9

PL18

+PP

PL18

H633-9

H634-8

TB11

625

633C

+PP

R23

S1/2.01

SIG_1/4.28

600

TB11

YEL_G634-2

OPEN

(CL)

CCW

(Schematic continues on next page.)

YEL_G632-R

YEL_G633-1

COM

WHTBLK

VMI

VALVE

ACTUATOR

(FLOATING)

GAS & AIR

MODULATING

(OP)

RED_G630-B WHT_G630-W

607A

602A

TB11

611A

610A 610B

609

H603-4

+PP

PL19

H602-2

603A 603B 603C

+PP

PL19

+PP

PL16

H603-2

3K1

FSG

6K1

MICROCOMPUTER

(L1)

426B

21 42

TB11

(FLAME SAFEGUARD)

(PLUG-IN TYPE

CONTROLLER)

617A

2K2

621C

107

5K12K11K1

621B

COM

618

613A

4K1

FIER

FSG

AMPLI

FLAME

FSG-F

FSG-G

(FLAME ROD)

HL22

H603-1

+PP

PL16

201A

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

(FSG) CONTROLLER.

LIGHTS ARE PART OF THE FLAMESAFEGUARD

1.POWER, PILOT & MAIN VALVE INDICATION

NOTE:

631

632

633

634

635

636

90 McQuay IM 738-2

Figure 98: Standard Mod, furnace control (1000 MBh), continued

(THRU 1/2 P.S.I.)

COCKCOCK

SHUTOFFSHUTOFF

(THRU 1/2 P.S.I.)

PIPING DIAGRAMPIPING DIAGRAM

Wiring Diagrams

COCKAIR COCK

SHUTOFFSHUTOFF

OVER 1/2 P.S.I.

REG.REG.

HIGH PRESS.

(Schematic continues on the previous page.)

WHEN THE ROOFTOP UNIT IS ENERGIZED 120 VOLT POWER IS SUPPLIED TO THE SYSTEM ON-OFF SWITCH (S1), TO BURNER ON-OFF SWITCH (S3) AND 24 VOLTS TO THE (BO#11)

CONTACTS ON THE MAIN CTRL BRD (MCB). BURNER ON-OFF SWITCH (S3) WILL POWER THE MODULATING GAS VALVE ACTUATOR (VM1) AND TERMINAL #5(L1) ON THE FLAME

SEQUENCE OF OPERATION

WHEN 120 VOLT

THE PILOT FLAME WILL IGNITE AND BE DETECTED BY THE FLAME SAFEGUARD THROUGH

ALSO, THE FLAME SAFEGUARD CONTAINS "LED'S" (LOWER LEFT CORNER) THAT WILL GLOW TO INDICATE OPERATION.

THE RELAY DRIVES THE GAS VALVE ACTUATOR (VM1) TO THE MINIMUM FIRING RATE POSITION WHENEVER THE FLAME IS NOT

UPON DETECTION OF PILOT FLAME, TERMINAL #10 (IGNITION TRANSFORMER--IT) WILL BE DE-ENERGIZED AND TERMINAL #9 (MAIN GAS VALVES--GV2 & GV3)

THE BURNER COMBUSTION AIR BLOWER MOTOR (BM). WHENEVER POWER IS RESTORED TO THE FLAME SAFEGUARD, THE FLAME SAFEGUARD WILL GO THROUGH A 10 SECOND

CONTROL (FLC) AND TERMINAL #6 ON THE FLAME SAFEQUARD (FSG) IS POWERED. THE FLAME SAFEGUARD THEN ENERGIZES ITS TERMINAL #4, WHICH POWERS

SAFEGUARD (FSG). UPON A CALL FOR HEAT, THE CONTROL SYSTEM WILL CLOSE (BO#11) ON THE MAIN CTRL BRD (MCB), THUS ENERGIZING RELAY (R20).

POWER IS FURNISHED THROUGH THE SYSTEM ON-OFF SWITCH (S1), THROUGH THE BURNER ON-OFF SWITCH (S3), THROUGH RELAY (R20) CONTACTS, THROUGH THE HIGH LIMIT

BLOWER OPERATION IS SENSED BY THE AIR SWITCH (AS), WHICH MAKES TERMINAL #6 TO #7. AFTER A 90 SECOND PREPURGE PERIOD, TERMINAL #8 (FIRST GAS VALVE

INITIATION PERIOD BEFORE THE PREPURGE PERIOD WILL BEGIN.

THE FLAME ROD (FD).

(PILOT)--GV1) AND TERMINAL #10 (IGNITION TRANSFORMER--IT) WILL BE ENERGIZED.

GAS VALVE AND COMBUSTION AIR DAMPER AND CAN SET THE FIRING RATE BETWEEN 33% AND 100% OF NORMAL RATE. WHEN THE MAIN CONTROL SYSTEM CLOSES (BO#10) ON THE

WHENEVER THE BURNER IS IN OPERATION ITS FIRING RATE WILL BE DETERMINED BY THE "FLOATING" GAS VALVE ACTUATOR (VM1). THIS ACTUATOR POSITIONS THE BUTTERFLY

WILL BE ENERGIZED AND THE MAIN FLAME WILL COME ON.

ON, AND HOLDS IT THERE UNTIL THE FLAME HAS LIT AND BEEN PROVEN.

LOW FIRE START IS PROVIDED BY RELAY (R23).

REG.

MAIN

PRESS.

COCKCOCK

PILOT

PRESS. REG.PRESS. REG.

GV2GV2

GV3

MAIN GAS VALVES

TEST

GAS

MOD.

TEST

(BO#9) OR (BO#10) ON THE MAIN CONTROL BOARD (MCB) ARE CLOSED THE ACTUATOR WILL REMAIN AT ITS PRESENT POSITION. THE HEATING CAPACITY IS MONITORED BY THE

POSITION. WHEN THE MAIN CONTROL SYSTEM CLOSES (BO#9) ON THE MAIN CTRL BRD.(MCB), THE ACTUATOR WILL REPOSITION TOWARD A LOWER FIRING RATE. IF NEITHER

MAIN CTRL BRD.(MCB), THE GAS VALVE ACTUATOR WILL REPOSITION TOWARD A HIGHER FIRING RATE UNTIL EITHER (BO#10) OPENS OR THE ACTUATOR REACHES ITS MAXIMUM

MAIN CONTROL BOARD (MCB) THROUGH (AI#10) VIA A POSITION FEEDBACK POTENTIOMETER ON THE ACTUATOR (VM1).

DE-ENERGIZED, THUS DE-ENERGIZING THE BURNER. THE FLAME SAFEGUARD WOULD THEN BE ON SAFETY LOCKOUT AND WOULD REQUIRE MANUAL RESETTING. THE HEAT ALARM

RELAY (R24) WOULD THEN BE ENERGIZED AND WOULD THEN ENERGIZE THE REMOTE "HEAT FAIL" INDICATOR LIGHT AND SEND A FAIL SIGNAL TO BINARY INPUT #5 ON THE

IN THE EVENT THE PILOT FAILS TO IGNITE OR THE FLAME SAFEGUARD FAILS TO DETECT ITS FLAME WITHIN 10 SECONDS, TERMINALS #4, 8, 9, AND 10 WILL BE

IF THE UNIT OVERHEATS, THE HIGH LIMIT CONTROL (FLC) WILL CYCLE THE BURNER, LIMITING FURNACE TEMPERATURE TO THE LIMIT CONTROL SET POINT.

MICROTECH II MAIN CONTROL BOARD (MCB).

COCK

VALVE

CONN.

GV1

PILOT VALVE

TEST

CONN.

AIR

BURNER

BLOWER

SWITCH

AIR

DAMPER

McQuay IM 738-2 91

Wiring Diagrams

/1.68 /1.68

8008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368

Figure 99: RPS 60 condensing unit control (with scroll compressors)

/2.68

T1_115VAC T1_N

T2_115VAC

168C

203B

115V

A1 A2

(OPEN OUTPUT)

BO8

NOCOM

807

NOCOM

GRD

(Schematic continues on next page.)

711

808 815

+PP

RESISTOR

1.3K OHM, 2W

BI4

MMP1

INPUTS

BI=BINARY

BI12

PL25

+NB

HTR1

+PP

PL25

814B

12(32)11(31)

711

H814-12

+PP

PL25

814A

BI5

AI=ANALOG

H815-7

2222222

MP1JH816-5

H815-6

+NB

2221

817

+PP

PL25

168A

115VAC/8.14

LP1

+NB

H815-11

+PP

PL25

815A

BI6

COM2

+PP

MP1

+PP

PL25

H817-4

H817-3

PL25

BO1

(COMPR #1)

817A 817B 817C

805A

N_24/8.38

REF/2.11

N2+/2.10

N2-/2.10

210D

210C

209C

210D

REF/8.40N2+/8.39

N2-/8.39

209C

210C

GRD303129

TB1E

TB1ETB1E

24V

CLASS 2

803A

24C

N2+

TB1E

24V

J10

BI1

REF

N2-

B01

B02

DISABLEENABLE

BUS

JUST UNDER

JUMPERS

(JUMPER LOCATED

BI10

BI9

BI7

809A

1413

808A

807A

1413

817

836

COM1

COMM. CARD)

822

BI2

COMPR.

CONTROL

BOARD

BI8

PS1

BI3

CCB1

812A

BI11

+PP

PL27

H820-3

+NB

819A

MMP3

+PP

12(32)11(31)

HTR3

H820-2

PL27

727

168A

NOCOM

2222222

2221

822

+PP

PL27

115VAC/8.19

MP3J

+NB

H821-8

809 820

727

M11

1M2

+PP

PL27

H822-1

MP3

+PP

PL9

PL10

+PP

H822-12

+PP

PL27

822A 822B

BO2

(COMPR #3)

NOCOM

BO9

(COMPR #5)

20 NOCOM

H830-3

SV5

+NB

H831-4

SV1

+NB

H830-4

H831-2

+PP

PL10

PL9

+PP

830A

NOCOM

BO4

NOCOM

BO3

J823A

1110

+PP

PL27

709

705

757

M12

A1 A2

M13

A1 A2

834A

833A

832A

13 NOCOM

BO6

NOCOM

BO7

BO5

J823B

H827-11

HP3

+NB

813A

H827-10

+PP

PL27

823A 823B

805B

7NO7

BO7

207

115VAC/8.15

MCB

jprs

24V SRC

115VAC/8.20

CS1

168A

92 McQuay IM 738-2

Figure 99: RPS 60 condensing unit control (with scroll compressors), continued

Wiring Diagrams

840

A1 A2

N_24/8.06

805A

N2+/8.09

WHT

BLK

N2-/8.08

REF/8.09

DRN

847B

MMP2

841 848

719

H850-7H850-12

+PP

+NB

852B

12(32)11(31)

MMP4

+PP

PL26

H848-4

2222222

+NB

HTR2

+PP

PL26

MP2J

H848-9

+PP

MP2

+NB

PL26

2221

850

12(32)11(31)

H849-8

719

+PP

PL26

168A

115VAC/8.48

+PP

PL26

+PP

PL28

HTR4

735

H853-4

H853-9

PL28

168A

2222222

MP4J

2221

855

+PP

PL28

115VAC/8.53

+NB

H854-8

735

842 853

+PP

PL28

H855-7

MP4

+PP

PL10

H855-6

+PP

PL28

H863-6

SV6

+NB

H863-1

720

762

724

M22

A1 A2

M21

M23

A1 A2

PL9

+PP

865A

866A

867A

H864-5

SV2

+NB

H864-1

LP2

BI4

INPUTS

BI=BINARY

H847-3

+PP

PL26

847A

BI5

AI=ANALOG

BI12

+NB

+PP

BI6

H848-2

PL26

848A

COM2

BO1

(COMPR #2)

+PP

PL10

PL9

855A 855B

NOCOM

BO2

(COMPR #4)

NOCOM

BO9

(COMPR #6)

NOCOM

+PP

864A

NOCOM

BO3

10 NOCOM

BO6

BO4

NOCOM

BO5

(OPEN OUTPUT)

NOCOM

BO8

NOCOM

BO7

GRD

209C

210C

210D

(Schematic continues on previous page.)

N2+

B01

B02

DISABLEENABLE

BUS

JUST UNDER

JUMPERS

24V

J10

(JUMPER LOCATED

BI10

BI9

BI7

BI1

REF

24C

N2-

COM1

COMM. CARD)

BI2

COMPR.

CONTROL

BOARD

BI8

BI3

CCB2

BI11

850A 850B 850C

J856A

J856B

+PP

PL28

841A

842A

1413

845A

855

PS2

840A

838A

1413

850

869

115VAC/8.48

115VAC/8.53

HP4

+NB

H860-10 H860-11

+PP

PL28

10 11

856A 856B

CS2

3839404142

444546

168A

474849

168A

525354

5556575859

6061626364

656667

McQuay IM 738-2 93

Wiring Diagrams

Figure 100: RPS 135 condensing unit control (with reciprocating compressors)

168C

OP1/8.48

824

706

808 815

710

168C

805A

N_24/8.38

REF/2.11

N2+/2.10

N2-/2.10

210D

209C

210C

209C

N2-/8.39

REF/8.40N2+/8.39

RESISTOR

1.3K OHM, 2W

GRD303129

TB1E

TB1ETB1E

24V

115V

CLASS 2

803A

24C

N2+

TB1E

24V

BI1

REF

N2-

B01

B02

DISABLEENABLE

BUS

JUST UNDER

JUMPERS

(JUMPER LOCATED

BI9

BI7

J10

809A

808A

807A

1413

817

836

BI3

BI2

COMPR.

BOARD

CONTROL

BI8

BI4

CCB1

BI11

812A

PS1

COM1

COMM. CARD)

BI10

1413

822

H805

120

818C

2 MIN

817

TD5

OP1

H817D

TB3

+PP

MP1J

PL25

H817-4

MP1

+NB

H816-5

H817-3

PL25

+PP

PL25

TD3

TB3

H817C

816

OP1

+NB

38 40

H817B

COM2

NOCOM

BO1

(COMPR #1)

818A 818B

819A

MMP3

BEING ENERGIZED)

5 SECONDS AFTER

(TD3 CLOSES FOR

H800B

+PP

PL25

+NB

H815-7

2222222

+NB

HTR1

H815-6

+PP

PL25

2221

817

814B

12(32)11(31)

706

MMP1

+PP

168A

115VAC/8.14

LP1

+NB

H814-12

+PP

H815-11

PL25

+PP

PL25

814A

815A

BI6

BI5

INPUTS

BI=BINARY

AI=ANALOG

BI12

817A 817B 817C 817D

813A

7NO7

BO7

207

115VAC/8.15

MCB

jprs

805B

CS1

203B

/2.68

T2_115VAC

/1.68 /1.68

T1_115VAC T1_N

800

801

802

803

804

168A

805

806

807

808

809

810

24V SRC

168A

811

812

813

814

815

816

817

818

OP3/8.53

739

809 820

743

H805

H800B

120

2 MIN

+PP

PL27

+NB

H820-3

2222222

+NB

HTR3

H820-2

+PP

PL27

2221

822

12(32)11(31)

739

+PP

168A

115VAC/8.19

115VAC/8.20

OP3

H822D

MP3J

H821-8

PL27

822

TD7

TB3

+PP

PL27

H822-1

MP3

+NB

2222222

+PP

PL10

H822-12

+PP

PL27

TB3

H822B

821

OP3

+NB

45 47

H822A

822A 822B

NOCOM

BO2

(COMPR #3)

1110

+PP

PL27

BO9

(COMPR #5)

+PP

H827-11

HP3

+NB

H827-10

+PP

PL27

823A 823D 823B 823C

+NB

819

+PP

NOCOM

PL25

HP1

H823-10

PL25

H830-3

SV5

+NB

COMPR #1

+NB

U1_1

H830-4

+PP

PL10

+PP

PL25

830A

829A

NOCOM

BO3

H823-2

705

757

M12

A1 A2

M11

A1 A2

832B

835

R11

PL9

+PP

832B

832A

H831-4

SV1

+NB

H831-2

PL9

+PP

NOCOM

BO6

BO4

NOCOM

BO5

BO7

823A

709

834A

807

832

719

M14

A1 A2

R11

M13

A1 A2

835A

NOCOM

BO8

NOCOM

GRD

(Schematic continues on next page.)

168A

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

94 McQuay IM 738-2

Figure 100: RPS 135 condensing unit control (with reciprocating compressors), continued

Wiring Diagrams

M23

840

865

743

M24

A1 A2

R12

A1 A2

868A

NOCOM

BO8

NOCOM

GRD

723

850

TB3

PL26

H850-7

H850-12

PL26

TB3

H850C

H850B

(COMPR #2)

850A 850B 850C 850D

857

841 848

727

851C

+PP

TD6

+NB

+PP

852A

12(32)11(31)

MMP4

168A168A

TD4

851A 851B

849

BEING ENERGIZED)

5 SECONDS AFTER

(TD3 CLOSES FOR

NOCOM

PL28

756

115VAC/8.52

PL28

H853-4

HTR4

OP3/8.21

H853-9

2221

115VAC/8.52

756

842 853

760

JPR

120

2 MIN

855

TD8

OP4

+NB

2222222

H855D

TB3

MP4J

+PP

PL28

H855-7

MP4

+NB

855

+PP

PL10

+PP

+NB

+PP

NOCOM

PL26

HP2

H856-10

PL26

222222

H863-6

SV6

+NB

COMPR #2

+NB

H863-1

U1_2

+PP

PL10

PL26

826A

NOCOM

BO3

H856-11

10 11

H855-6

H854-8

+PP

PL28

+PP

PL28

TB3

H855B

854

OP4

+NB

H855A

855A 855B

BO2

(COMPR #4)

NOCOM

+PP

PL28

BO9

(COMPR #6)

H860-11

852

HP4

+NB

H860-10

+PP

PL28

10 11

+PP

+NB

+PP

BO4

PL9

H864-5

SV2

H864-1

PL9

864A

856A

729

762

733

M22

A1 A2

M21

A1 A2

865B

868

R12

867A

865A

NOCOM

BO6

NOCOM

BO7

BO5

856A

168C168C

OP1/8.16

JPR

120

2 MIN

+PP

PL26

OP2

+NB

H848-4

2222222

H850D

+NB

HTR2

+PP

MP2J

H848-9

805A

N_24/8.06

847B

MMP2

WHT

209C

N2+/8.09

BLK

210C

N2-/8.08

210D

REF/8.09

DRN

+PP

BI1

(JUMPER LOCATED

JUST UNDER

COMM. CARD)

BI10

COM1

COMPR.

CONTROL

BI2

BOARD

BI8

REF

24C

N2-

N2+

B01

B02

DISABLEENABLE

BUS

JUMPERS

(Schematic continues on previous page.)

24V

BI9

BI7

J10

842A

1413

841A

855

BI5

BI3

BI4

INPUTS

CCB2

BI=BINARY

AI=ANALOG

BI12

BI11

845A

PS2

+PP

12(32)11(31)

723

H847-3

PL26

847A

PL26

168A

+NB

+PP

BI6

2221

850

H849-8

+PP

PL26

115VAC/8.47

LP2

H848-2

PL26

848A

COM2

MP2

+NB

+PP

OP2

+NB

BO1

840A

1413

850

869

115VAC/8.48

838A

CS2

837

838

839

840

841

842

843

844

168A

845

846

847

848

849

850

851

852

853

856A 656D 856B 856C

854

855

856

857

858

859

860

861

862

863

864

865

866

867

868

869

870

McQuay IM 738-2 95

Wiring Diagrams

Figure 101: CV fan control (SAF and RAF)

/3.11

115VAC_GF/1 T1_N

11(31)

T3_24V

SOURCE 9-16

MCB

WIRED INTERNAL

TO MOTHERBOARD

207

SRC 9-16

MMP10

12(32) 11(31)

jprs

MCB

TB2

MMP20

TB2

12(32)

1 1NO

207

SUPPLY FAN

MCB

2 2NO

207

RETURN FAN

BO1

24V SRC

401A

jprs

BO2

24V SRC

404A

R67

401

426C426B426A

/3.11

T3_COM

R67

R68

M10

A2A1

/1.68

R68

404

431A

M20

A2A1

Figure 102: Light and receptacle power

FIELD SUPPLIED 115V/60/1

REC1

TB7

CP SL

GRD

1004B

1003B1003A

TB7

1005B1005A

SLCP

PL31

PL32

H1006-1

96 McQuay IM 738-2

H775

S10

H775

S11

H775

REC10

REC11

LT10

BLK WHT

LT11

BLK WHT

H776

G1009

H776

G1012

H1006-2

H1010-2H1010-1

PL31

PL32

TB7

G1004

Unit Options

Enthalpy Control

Outside Air Enthalpy Control (OAE)

Units with MicroTech II control and an economizer come standard with an electromechanical enthalpy control device (OAE) that senses both the humidity and temperature of the outside air entering the unit. This device has an enthalpy scale marked A through D. Table 24 shows the control points at 50% RH for settings A through D. Figure 103 shows this scale on a psychrometric chart. When the outside air conditions exceed the setting of the device, the outside air dampers are positioned to the minimum outside air intake position by the MicroTech II

controller.

Table 24: Enthalpy control settings

Control curve Control point temperature at 50% RH

A73°F (23°C) B70°F (21°C) C 67°F (19*C) D63°F (17°C)

Differential Enthalpy Control (OAE/RAE)

An optional electric differential enthalpy control arrangement (OAE/RAE) is available on units with MicroTech II control. In this configuration a solid-state humidity and temperature sensing device is located in both the return (RAE) and outside intake (OAE) airstreams. This OAE device has the same A through D scale as the device described above. However, with the OAE/RAE arrangement the switch on, OAE must be set all the way past the D setting. With this done, the MicroTech II controller adjusts the return and outside air dampers to use the airstream with the lowest enthalpy.

Ground Fault Protection

The ground fault protection is designed to protect motors from destructive arcing ground faults. The system consists of a ground fault relay and a ground fault current sensor. The ground fault relay employs solid state circuits that will instantly trip and open a set of relay contacts in the 115-volt control circuit to shut the unit down whenever a ground fault condition exists. The ground fault relay is self powered. The ground fault sensor is a current transformer type of device

located on the load side of the power block through which the power wires of all phases are run.

Figure 103: Enthalpy control settings

8 5

9 0

9 5

1 0 0

( 2 9 . 5 )

4 6

4 4

4 2

8 0

( 2 6 . 5 )

4 0

3 8

3 6

3 4

3 2

3 0

2 8

2 6

E N T H A L P Y  B T U P E R P O U N D D R Y A I R

2 4

2 2

2 0

1 8

1 6

1 4

1 2

( 1 . 5 )

4 5 ( 7 )

4 0

( 4 . 5 )

3 5

4 0

4 5

( 1 . 5 )

( 4 . 5 )

( 7 )

6 0

( 1 5 . 5 )

5 5

( 1 3 )

5 0

( 1 0 )

5 0

5 5

6 0

( 1 0 )

( 1 3 )

( 1 5 . 5 )

( 1 8 . 5 )

6 5

( 1 8 . 5 )

7 5

( 2 4 )

7 0

( 2 1 )

6 5

7 0

7 5

( 2 1 )

( 2 4 )

( 3 2 )

0 . 8 0

0 . 9 0

0 . 7 0

0 . 6 0

0 . 5 0

8 0

8 5

9 0

( 2 6 . 5 )

( 2 9 . 5 )

( 3 2 )

1 0 5

( 3 5 )

( 3 8 )

( 4 0 . 5 )

R E L A T I V E

H U M I D I T Y

0 . 4 0

0 . 3 0

0 . 2 0

0 . 1 0

9 5

1 0 0

1 0 5

0 . 5 )

( 3 5 )

( 3 8 )

( 4

Phase Voltage Monitor

The phase voltage monitor (see page 134) protects against high voltage, phase imbalance, and phase loss (single phasing) when any one of three line voltages drops to 74% or less of setting. This device also protects against phase reversal when improper phase sequence is applied to equipment, and low voltage (brownout) when all three line voltages drop to 90% or less of setting. An indicator run light is ON when all phase voltages are within specified limits. The phase voltage monitor is located on the load side of the power block with a set of contacts wired to the 115-volt control circuit to shut the unit down whenever the phase voltages are outside the specified limits.

McQuay IM 738-2 97

Unit Options

Hot Gas Bypass

Hot gas bypass is a system for maintaining evaporator pressure at or above a minimum value. The purpose for regulating the hot gas into the distributor is to keep the velocity of the refrigerant as it passes through the evaporator high enough for proper oil return to the compressor when cooling load conditions are light.

The system consists of a combination of solenoid valves and a pressure regulating valve as shown in Figure 104. The solenoid valves are factory wired to open whenever the

Figure 104: Hot gas bypass system

Hot gas bypass line,

circuit #1

Hot gas bypass line,

circuit #2

Combination modulation

and solenoid valves

controller calls for the first stage of cooling. The pressure regulating valve starts to modulate open at 57 psig (393 kPa).

The regulating valve opening point can be determined by slowly reducing the system load or reducing the required discharge air temperature setting while observing the suction pressure. When the bypass valve starts to open, the refrigerant line on the evaporator side of the valve will begin to feel warm

to the touch.

CAUTION

Do not touch gas liner during valve checkout. The hot gas line can become hot enough in a short time to cause personal injury.

To evaporator

98 McQuay IM 738-2

Unit Options

SpeedTrol™ (N/A Unit Sizes 015C to 030C)

McQuay’s SpeedTrol system of head pressure control operates in conjunction with FanTrol by modulating the motor speed of the last condenser fan of each refrigeration circuit in response to condenser pressure. By varying the speed of the last condenser fan of each refrigeration circuit, the SpeedTrol option allows mechanical cooling operation in ambient temperatures down to 0°F (-18°C) provided the unit is not exposed to windy conditions. The system designer is responsible for assuring the condensing section is not exposed to excessive wind or air circulation. SpeedTrol controllers SC11 and SC21 sense refrigerant head pressure and vary the

fan speed accordingly. When the pressure rises, SpeedTrol increases the fan speed; when the pressure falls, SpeedTrol decreases the fan speed. The SpeedTrol controller's throttling range is 140 to 200 psig (1212 to 1318 kPa) fixed.

The SpeedTrol fan motor is a single phase, 208/240-volt, thermally protected motor specially designed for variable speed application. Units with 460-volt power have a transformer mounted inside the condenser fan compartment to step the voltage down to 230 volts for the SpeedTrol motor. A portion of a typical SpeedTrol power circuit schematic is shown in Figure 105.

McQuay IM 738-2 99

Unit Options

External Time Clock

You can use an external time clock as an alternative to (or in addition to) the MicroTech II controller’s internal scheduling function. The external timing mechanism is set up to open and close the circuit between field terminals 101 and 102. When the circuit is open, power is not supplied to binary input MCB-BI1. This is the normal condition where the controller follows the programmable internal schedule. When the circuit is closed, power is fed to BI1. The MicroTech II controller responds by placing the unit in the occupied mode, overriding any set internal schedule.

For more information, see the “Digital Inputs” section of Bulletin No. IM 696, “MicroTech II Applied Rooftop Unit Controller.”

Smoke and Fire Protection

McQuay optionally offers factory installed outdoor air, return air, and exhaust air dampers as well as smoke detectors in the supply and return air openings, complete with wiring and control. These components often are used in the building’s smoke, fume, and fire protection systems. However, due to the wide variation in building design and ambient operating conditions into which our units are applied, we do not represent or warrant that our products will be fit and sufficient for smoke, fume, and fire control purposes. The owner and a fully qualified building designer are responsible for meeting

all local and NFPA building code requirements with respect to smoke, fume, and fire control.

WARNING

Improper smoke, fire, or fume air handling can result in severe personal injury or death.

Smoke Detectors

Optional smoke detectors can be located at the supply and return openings. The wiring for these smoke detectors is shown on any of the “Typical Main Control Circuit” wiring schematics within the “Wiring Diagrams” section on pages 74–103.

The sequence of operation for these detectors is as follows: When smoke is detected by either sensor, the normally closed sensor contacts open. This removes power from binary input BI8 on the Main Control Board.

The MicroTech II controller responds by shutting down the unit. The controller is placed in the Alarm Off state and cannot be restarted until the alarm is manually cleared. Refer to the operation manual supplied with the unit for information on clearing alarms (OM138 or OM137).

The smoke detectors themselves must be reset manually once they have tripped. Power must be cycled to the smoke detector to reset.

Figure 105: SpeedTrol schematic

4L13 757-1

4L14

4L13 762-1

4L14

F11

759-1

F12

764-1

M11

832

M21

865

T1L1

T3L3

T1L1

T3L3

Freeze Protection

An optional freezestat is available on units with MicroTech II control that have hot water, chilled water, or steam heating coils. The sensing element is located on the downstream side of the heating coil in the heating section of the unit. If the freezestat detects a freezing condition and closes, the MicroTech II controller takes different actions, depending on whether the fans are on or off. The freezestat is an auto reset type of control; however, the controller alarm that it causes is manually reset if the fan is on and auto reset if the fan is off.

+NB

COND-FAN11

C11

C21

HCF11-1

HCF11-2

HCF11-3

1111111

HCF21-1

HCF21-2

HCF21-3

1111111

MTR

+NB

COND-FAN21

MTR

HCF11-S1

HCF11-S3

H739-2

3-2 3-1

H741-2

HCF21-S1

HCF21-S3

H738-2

H740-2

+NB

SC11

24V

+NB

SC21

Fan On Operation

If the freezestat detects a freezing condition while the fan is on, the MicroTech II controller shuts down the fans, closes the outdoor air dampers, opens the heating valve, and sets a 10minute timer. The MicroTech II controller’s active alarm is “Freeze Fault.”

When the 10-minute timer expires, the controller begins checking the freezestat again. If the freezestat is open, the heating valve closes. If the freezestat closes again, the heating valve opens, and the 10-minute timer resets.

100 McQuay IM 738-2

McQuay RCS015 Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Introduction

Unit Nameplate

Gas Burner Nameplate

Hazard Identification Information

Compressor Nameplate

Unit Description

Typical Component Locations

Condenser Fan Arrangement

Refrigeration Piping

Control Locations

Control Panel

Controls, Settings, and Functions

Mechanical Installation

Unit Clearances

Ventilation Clearance

Overhead Clearance

IBC Seismic Compliant Units

Roof Curb Arrangement

Post and Rail Arrangement

Post and Rail Mounting

Rigging and Handling

Reassembly of Split Units

RPS/RDT Factory Split at Condensing Unit

RFS/RCS Permanent Split Systems

Unit Piping

Steam Coil Piping

Steam Piping Recommendations

Steam Trap Recommendations

Damper Assemblies

Cabinet Weather Protection

Installing Ductwork

Installing Duct Static Pressure Sensor Taps

Installing Building Static Pressure Sensor Taps

Electrical Installation

Field Power Wiring

Field Control Wiring

Preparing Unit for Operation

Spring Isolated Fans

Relief Damper Tie-Down

Adjusting Scroll Dampers

Adjusting Supply Fan Thrust Restraints

Sequences of Operation

Power-up

Fan Operation

Economizer Operation

Mechanical Cooling Operation

Heating

Wiring Diagrams

Unit Options

Enthalpy Control

Hot Gas Bypass

SpeedTrol™ (N/A Unit Sizes 015C to 030C)

External Time Clock

Smoke and Fire Protection

Smoke Detectors

Freeze Protection